serv1855 (345d) _txt

SERV1855April 2008

TECHNICAL PRESENTATION

345D HYDRAULIC EXCAVATORINTRODUCTION

Service Training Meeting Guide(STMG)

GLOBAL SERVICE LEARNING

345D HYDRAULIC EXCAVATOR -INTRODUCTION

AUDIENCEService personnel who understand the principles of machine systems operation, diagnosticequipment, and testing and adjusting procedures.

CONTENTThis presentation discusses the component locations and systems operation of the 345DHydraulic Excavator. Basic engine and machine component locations will be discussed. Also,the implement hydraulics will be covered.

OBJECTIVESAfter learning the information in this presentation, the serviceman will be able to:

1. locate and identify the major components in the engine and implement systems; 2. explain the operation of each component in the engine and implement systems; and3. trace the flow of oil through the implement systems.

REFERENCES345C Hydraulic Excavator Specalog AEHQ5687345C Hydraulic Excavator Parts Book SEBP4205345C Hydraulic Excavator Operation and Maintenance Manual SEBU7861345C Hydraulic Excavator System Operation (Hydraulic) RENR7324345C Hydraulic Excavator Testing and Adjusting RENR7325345C Hydraulic Excavator Specifications Manual RENR7283345C Hydraulic Excavator System Operation (C11 and C13) RENR9888345D Hydraulic Excavator Specalog AEHQ5940345D L Excavator - Parts Manual SEBP5184345D Excavator - Operation and Maintenance Manual SEBU8300

PREREQUISITESInteractive Video Course "Fundamentals of Mobile Hydraulics" TEMV9001Interactive Video Course "Fundamentals of Machine Electronics" TEMV9002

Estimated Time: 10 HoursVisuals: 122 IllustrationsHandouts: 54 PagesForm: SERV1855Date: 04/08

© 2008 Caterpillar Inc.

TABLE OF CONTENTS

INTRODUCTION ........................................................................................................................5

MACHINE WALKAROUND ......................................................................................................7

OPERATOR'S STATION............................................................................................................17

ENGINE......................................................................................................................................34Left Side of Engine...............................................................................................................38Right Side of Engine.............................................................................................................39Front of Engine .....................................................................................................................41

HYDRAULIC SYSTEMS..........................................................................................................43Power Shift Pressure System................................................................................................45Main Hydraulic Pumps ........................................................................................................46Pump Controls ......................................................................................................................52Pump Flow Decrease - due to increased pump load ............................................................58Pilot Hydraulic System.........................................................................................................61Hydraulic Activation Control Lever .....................................................................................66Two-Speed Travel Solenoid..................................................................................................70Pilot Logic Network .............................................................................................................72Straight Travel Mode ............................................................................................................73Pilot Control Valve ...............................................................................................................74

HYDRAULIC FAN SYSTEM ...................................................................................................76Hydraulic Fan Pump.............................................................................................................77Hydraulic Fan Pump Controls ..............................................................................................78Hydraulic Fan Motor ............................................................................................................84Main Control Valve...............................................................................................................85Bucket Hydraulic Circuit ......................................................................................................93Boom Hydraulic Circuit .......................................................................................................95Boom Down with Regeneration ...........................................................................................97Boom Drift Reduction Valve ................................................................................................98Boom Lowering Control Valve...........................................................................................100Boom Priority .....................................................................................................................102Stick Hydraulic Circuit .......................................................................................................105Stick Regeneration ..............................................................................................................109Stick Drift Reduction Valve ................................................................................................111Swing Hydraulic System ....................................................................................................113Swing Right Without Priority .............................................................................................115Swing Right With Priority ..................................................................................................118Swing Motor .......................................................................................................................119Swing Parking Brake ..........................................................................................................120Swing Motor Crossover Relief Valve.................................................................................121Swing Anti-reaction Valves ................................................................................................123

SERV1855 - 3 - Text Reference04/08

TRAVEL CIRCUIT ..................................................................................................................127Travel Motor .......................................................................................................................128Travel Motor Brake Release Valve.....................................................................................131Counterbalance Valve (Level Travel) .................................................................................133Counterbalance Valve Operation (Slope Travel) ................................................................134Travel Crossover Relief Valves (Machine Stop) ................................................................136Low Speed Travel ...............................................................................................................138High Speed Travel ..............................................................................................................139Final Drive ..........................................................................................................................140

RETURN HYDRAULIC CIRCUIT.........................................................................................141

WORK TOOLS ........................................................................................................................142

CONCLUSION.........................................................................................................................144

HYDRAULIC SCHEMATIC COLOR CODES ......................................................................145

VISUAL LIST ..........................................................................................................................147

LAB WORKSHEETS...............................................................................................................149

LAB WORKSHEET ANSWERS.............................................................................................176

HYDRAULIC SYSTEMS OPERATIONS POSTTEST ANSWERS......................................199



INTRODUCTION

The 345D is a direct replacement for the 345C Hydraulic Excavator. The 345D operating weight is approximately 45,375 Kg (100,040 lbs) for a Standard Machine. Thisweight classifies the 345D in the 45 metric ton class of excavators. The 345D is a versatilemachine capable of performing a wide range of tasks by using various work tools that areavailable.

The 345D is equipped with a C13 ACERT™ engine. The C13 ACERT™ engine utilizes the following technologies: Advanced Diesel Engine Management - Electronic Control Module (ADEM A4), Air-to-Air-Aftercooling (ATAAC), direct injection turbocharged (DI-T), and aMechanically Actuated Unit Fuel Injector (MEUI) system, which complies with Tier 3Emissions regulations and European Union Sound IIIA requirements. The engine is rated at 283 kW (380 hp) at 1800 rpm.

The 345D Hydraulic Excavator utilizes a Negative Flow Control (NFC) system for the mainimplement, hydraulic system. The NFC hydraulic system is a pressure control system that provides proportional control of the main implement pumps in order to provide maximumhydraulic horsepower, controllability, and fuel economy under a wide range of operating conditions.

345D HYDRAULIC EXCAVATORINTRODUCTION

© 2008 Caterpillar Inc.

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The 345D Hydraulic Excavator incorporates a new monitor panel similar to the 365C HydraulicExcavator which provides additional operating information to the operator. The machine isdesigned for improved operator comfort, serviceability, and ease of use.

This presentation discusses the component locations and systems operation of the 345DHydraulic Excavator.

The 345D Hydraulic Excavator integrates styling and an operator's station similar to the othermedium size 300 "D" Series Hydraulic Excavators.



MACHINE WALKAROUND

From the left side of the machine the following machine components are visible.

- Boom (1)

- Access door behind cab (2)

- Engine access cover (3)

- Stick (4)

- Bucket (5)

- Operator station (6)

- Access door to radiator compartment (7)

- Counterweight (8)

The 345D has an entirely new stick profile. The geometry has been optimized to provide amore cost efficient stick. In other words, the new stick has been designed to have the samereliability and durability of the 345C but is capable of lifting a larger capacity with faster cycletimes.

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The compartment behind the operator station includes the following components:

- Machine ECM (1)

- Window washer reservoir (2)

- Master disconnect switch and circuit breakers (3)

- Batteries (4)

- Vandalism guards (5)

- Engine coolant expansion tank (6)

- Secondary fuel filter (7)

- Primary fuel filter and water separator (8)

- Dual element, radial seal air filter (9)

NOTE: Additional attachment ECMs may also be mounted in this compartment.

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The 345D is available with a two-way control pattern change valve (1). The pattern changevalve permits changing the operator controls between SAE Excavator and SAE BackhoeLoader patterns. When changed, this valve redirects pilot oil to the corresponding control spoolin the main control valve group.

The pattern change valve is located in the compartment behind the operator's station.

In order to change the pattern, the technician removes the thumbscrew (3) and turns the shiftlever (2) to the right 90 degrees to select the alternate position. After the lever is turned, thethumbscrew (3) can be installed into a threaded hole in the new position. The screw preventsunwanted movement of the lever.

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A decal film (arrow) is included to identify the lever position in relation to the operator controlpattern.

The decal is located in the same compartment as the pattern change valve.

NOTE: To eliminate operator confusion, if the pattern change valve position ischanged, a plastic card in the operator's compartment must be turned to match thechosen pattern.

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The radiator access compartment is located in front of the counterweight on the left side of themachine. Although the door is hinged, bolts must be removed on the left side to access thecomponents.

This door provides access to assist in cleaning the following components.

- Air to air aftercooler (1)

- Hydraulic oil cooler (2)

- Engine radiator (3)

- Fuel cooler (4)

If the machine is equipped with the optional ether start system (5), it is also located in thiscompartment.

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The 345D is available with the optional counterweight removal system.

NOTE: The counterweight removal control valve is located in the pump compartment.

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This illustration shows access to the top of the machine from the right side.

The pump compartment access door (1) permits easy access to the hydraulic pumps.

The engine access cover (2) allows access to the engine from the top of the machine.

The machine hydraulic oil reservoir (3) is located between the pump compartment and thediesel fuel tank on the right side of the machine and is accessed from the top of the machine.

The diesel fuel filler cap (4) is accessed from the top of the machine.

The storage compartment (5) is located in the right front of the machine.

The ladder (6) on the front of the machine can be used for access to the top of the machine.

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The illustration shows the pump compartment on the right side of the machine. Some of thevisible components are:

- Engine oil filter (1)

- Engine oil S•O•S port (2)

- Fan pump (3)

- Main pumps (4)

- Counterweight removal valve (5)

- Auxiliary tool solenoids (6)

- Pilot filter (7)

- Two case drain filters (8). One case drain filter is for the pumps and the other filter is forthe motors.

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The illustration shows the following main pump components:

- Right pump (1)

- Power shift solenoid and proportional reducing valve (PSPRV) (2)

- Left pump (3)

- Suction line (4)

- Pilot pump (5)

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The undercarriage of the 345D has undergone improvements and is now offering a couple ofattachments. The main change includes the optimization of the track link geometry. Byoptimizing the geometry, the stress on the track link has been reduced resulting in longer linklife and reduced track cracking. There are two undercarriage attachments available on the345D. A cast idler eliminates the welding design the fabricated one had and reduces treaddeformation and early wear. The Positive Pin Retention 2 (PPR2), prevents loosening of thetrack pin from the track link. Both attachments are ideal for extreme applications or thoserequiring large amounts of travel.

The 345D has three undercarriage (1) options to meet regional transportation requirements andapplication needs: the long fixed gauge (L), the long variable gauge (LVG), and the long widevariable gauge (LWVG) undercarriages. The final drives (2) and travel motors are mounteddirectly to the roller frames in order to drive the tracks. The drive sprockets are bolted to thefinal drive case. This design keeps the drive sprocket in alignment with the track roller framesand tracks

NOTE: Throughout this training manual, machine travel forward and reversedirections are determined with the final drives and sprockets behind the operator'scompartment.

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OPERATOR'S STATION

The 345D operator's station maintains the improved visibility and operator comfort that the345C introduced. For operator comfort the cab offers a fully adjustable air suspended seat, withside-to-side shock absorption. Conveniently placed switches, gauges, information display, andcontrols improve operator comfort, awareness, and efficiency.

The operator's compartment can also be equipped with Falling Object Guard Structure (FOGS)bolted to the top of the compartment.

The monitor continuously monitors all important engine, implement hydraulic, and travelhydraulic functions. The system permits fast troubleshooting, resulting in increased excavatoravailability and reduced downtime for repairs. The monitor is flashable using CaterpillarElectronic Technician (Cat ET).

The cab improvements include:- new monitoring system- redesigned cab sealing- redesigned air ventilation system

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The operator's station provides a fully adjustable air suspended seat (1) with new arm rests,which provides maximum operator comfort.

The pattern change card (2) must be switched to display the correct hydraulic control pattern tomatch the pattern change valve in the compartment behind the cab.

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The left travel control (1) consists of a foot pedal and a hand lever that controls the left travel circuit. When pushed forward, the left track will rotate in the forward direction. When pulled to the rear, the left track will rotate in the reverse direction.

The right travel control (2) consists of a foot pedal and a hand lever that controls the right travel circuit. When pushed forward, the right track will rotate in the forward direction. When pulled to the rear, the right track will rotate in the reverse direction.

When the straight travel pedal (3) is pressed, a common pilot signal is sent to both the left and the right travel spools to shift them equally. This allows the right pump to supply oil to the right travel circuit and the left pump to supply oil to the left travel circuit.Pushing the straight travel pedal does not put the machine into the straight travel mode.

The straight travel mode is controlled hydraulically in the main control valve. Operation of thestraight travel mode is explained later in this presentation.

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The 345D Hydraulic Excavator features pilot operated joysticks. The joysticks direct pilot oilto the main control valve in order to actuate various implement functions on the machine.

The left joystick (1) controls the swing and stick functions of the machine.

The right joystick (2) controls the boom and bucket functions of the machine.

NOTE: The 345D is equipped with controls based upon the SAE excavator patternfrom the factory. The pattern change valve (if equipped) can be used to change thispattern to BHL controls if desired.

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Additional components and functions controlled by the switches on each joystick are:

- Blank (1)

- Horn (2)

- Medium pressure work tools 2 and 4 (3)

- Two-way pump flow work tools 2, 4, and 5 (4)

- One-way pump flow work tools 1 and 3 (5)

- One touch low idle (6)

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The 345D Hydraulic Excavator incorporates a monitor panel (1), like the small and medium300D and large 300C excavators, which provides additional operating information to theoperator.

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The monitor is a full color Liquid Crystal Display (LCD) graphic display that displays the various parameters of the machine.

- Alert Indicator (1) - illuminates continuously for level 2 warnings.

If one of the following level III critical conditions is logged, the alert indicator blinks ON and OFF.

- Engine oil pressure low

- Coolant temperature high

- Hydraulic oil temperature high

- Clock (2)

- Engine speed dial position indicator (3)

- Fuel gauge (4)

- Hydraulic oil temperature gauge (5)

- Engine coolant temperature gauge (6)

- Machine operating hours (7)

- Work tools (8)

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Under the normal default condition, the monitor screen is divided into the following four areas:

- The clock, engine speed dial position display, and gas station icon are displayed with agreen color.

- Three analog type gauges display the fuel level, the hydraulic oil temperature, and thecoolant temperature.

- Machine event information is displayed along with the appropriate icon and language.

- Multi-information area displays information for operator convenience. The "CAT" logomark is displayed when no information is available to display.

The operator or service technician can navigate through the different screens and informationabout the machine by pushing various buttons on the monitor panel. The buttons are locatedbelow the display area of the monitor.

The monitoring system display will display various warnings and information about thecondition of the machine. The monitoring system display has three gauges and a number ofalert indicators. Each gauge is dedicated to a parameter within a machine system. Themonitoring system will allow the user to do the following:

- View system status information

- View parameters

- View service intervals

- Perform calibrations

- Troubleshoot machine systems

Some of the possible parameters of the machine systems include: the fuel level, the enginecoolant temperature, and the hydraulic oil temperature. The gauges receive information fromsensors or senders that are connected to the controller. The controller uses the informationfrom each sensor input to calculate the value that is shown on the gauges.

The alert indicators notify the operator of an abnormal condition in a machine system. Thecontroller uses information from pressure switches, sensors, and other inputs in order todetermine when an abnormal condition is present. The controller sends a message to themonitoring system display. Then, the monitoring system will display a pop-up alert indicatorfor the machine system with the abnormal condition.


The monitor has eight buttons that are used to navigate through the different parameters on thescreen. The four directional buttons are: up (1), right (2), down (3), and left (4). The fournavigational buttons are: home (8), menu (7), back (5), and OK (6).

The directional buttons navigate the cursor through the various screens.

Pushing the home button changes the monitor screen to the default display. Pushing the menubutton changes the default display to the main menu display. Pushing the back button changesthe display to show the previous screen that was displayed. Pushing the OK button enters thedisplayed setting into memory.

NOTE: For more information on the 345D monitor, see monitor package "300D SeriesHydraulic Excavator, 345D Hydraulic Excavator, and 365C and 385C Large HydraulicExcavator Monitoring System", Form Number SERV7032.

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The hydraulic activation lever (1) has been redesigned for the 345D, however, its purpose isstill the same. With the lever in the DOWN position (shown), the hydraulic activation solenoidis in the de-activated position. The lever must be in this position in order to start the machine.

With the hydraulic activation lever in the UP position, the hydraulic activation solenoid is in theactivated position. The lever must be in this position before any of the implement controls areable to function.

The ground level, emergency engine shutoff switch (2) is located on the bottom of the seatbase.

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Below the operator's seat in the cab is the ground level, emergency engine shutoff switch(arrow).

This switch will shut off the machine without having to climb into the cab. The key startswitch must be cycled for the machine to operate again after the emergency shutoff switch isreturned to the RUN position.

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The operator functions incorporated into the right side of the operator station are:

- Engine speed dial switch (1)

- Key start switch (2)

- Cigar lighter (3)

- Soft switch panel (4)

- Rocker switches (5)

- HVAC controls (6)

- Radio (7)

NOTE: See the 345D Operation and Maintenance Manual for complete details on allswitches and buttons.

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The soft switch panel is a panel of switches located on the right hand side of the operator'scompartment that either turns a function ON/OFF or allows the operator to toggle throughdifferent modes of the selected function.

The soft switches provide the operator with the following functions:

Two-speed travel (1): When the button is pushed the travel speed is toggled between thetortoise and rabbit speeds.

- The rabbit indicator indicates automatic speed change. In this setting the travel motorswill upstroke and destroke as travel pressure changes in order to allow high speed travelof the machine.

- The tortoise indicator indicates low speed. In this setting, the travel speed will be limitedby keeping the travel motors upstroked in order to maximize travel torque.

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Automatic Engine Speed Control (AESC) Switch (2): The AESC function automaticallyreduces engine speed while there is no hydraulic demand, which reduces noise and fuelconsumption.

- The AESC switch disables and enables the AESC function.

- When disabled, the AESC reduces the engine speed by 100 rpm after there has been nohydraulic demand for approximately three seconds. This function occurs at all times,regardless of the switch setting.

- When enabled, the AESC reduces the engine rpm to approximately 1300 rpm after therehas been no hydraulic demand for three seconds. When enabled, the LED above theAESC switch is illuminated. In order to deactivate this function, press the switch untilthe LED is no longer illuminated.

- The second stage AESC delay times and rpms can be changed by using the monitor orCaterpillar Electronic Technician (ET).

Travel alarm cancel (3): The travel alarm cancel switch is a momentary switch.

- The travel alarm sounds when travel is detected.

- The travel alarm stops immediately if the travel alarm cancel switch is depressed.

- The travel alarm switch is reset every time the travel pressure switch opens.

Work tool switch (4): The work tool switch displays the selected work tool on the monitordisplay. Press the switch repeatedly in order to change the selected work tool.

Work lights (5): The work lights switch toggles between the different work light combinations.

- Pattern 1 - Chassis work lights and cab work lights.

- Pattern 2 - Chassis work lights, cab work lights, and boom work lights.

Upper window wipers (6): The wiper switch toggles between the different modes of thewipers.

- Six second delay.

- Three second delay.

- Continuous operation.

- Off.



Upper window washer (7): The windshield washer fluid switch is a momentary switch.

- When the switch is pressed, washer fluid will spray from the nozzle. The window wiperwill also operate while the switch is depressed. Approximately three seconds after theswitch is released, the window wiper will stop.

Heavy lift (8): The heavy lift mode can be selected to boost lifting capability and provideimproved controllability of heavy loads.

- When heavy lift is turned ON, the main relief valve increases from 35,000 kPa (5070 psi)to 38,000 kPa (5500 psi), making it possible to operate at the high pressure.

- In heavy lift mode, the maximum engine speed is limited to engine speed dial position 6 (1600 rpm).

- Maximum hydraulic flow is restricted to 60%.

The rocker switches are two-position switches used to turn the functions ON or OFF. Therocker switches provides the operator with the following functions:

Fine swing control (1)

- The top position activates fine swing control. Fine swing control improves the swingcontrol during swing deceleration.

- The bottom position deactivates fine swing control.

Lower window wipers (2)

- The top position activates the wipers.

- The bottom position deactivates the wipers.

Lower window washer (3)

- The top position activates the windshield washer fluid.

- The bottom position deactivates the windshield washer fluid.

Quick Coupler switch (4)

Seat heater switch (5)

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The back-up switches are located behind the right armrest. The back-up switch (3) togglesbetween back-up and auto. The back-up switch (2) controls the engine rpm.

In the BACK-UP position, the back-up switch (3) sends a fixed power shift pressure to thepumps. The fixed power shift pressure limits maximum pump output and allows the machineto continue operating in a Derate Mode. Machine productivity will be limited while themachine is in Back-up Mode.

The back-up switch (2) is used to control the engine speed while the Back-up Mode is active.The back-up switch (2) toggles to increase and decrease engine speed. Holding the speedswitch in the DOWN position will cause the engine to go to 0 rpm.

The diagnostic connector (1) is located inside of the operators station. It is located behind theright armrest, beside the back-up switches.

The diagnostic connector is used to connect Cat ET to the machine.

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ENGINE

The 345D is equipped with a C13 ACERT™ Engine with a rating of 283 kW (380 hp) at 1800 rpm. This represents approximately a 10% increase over the 345C. The C13 ACERT™incorporates the following state-of-the-art technologies to meet US EPA Tier III regulatedemission levels:

- Advanced Diesel Engine Management (ADEM A4)

- Air to Air Aftercooler (ATAAC)

- Electronically Actuated Unit Fuel Injection (EUI) System

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The fuel system priming switch is located in the compartment behind the cab and above theprimary fuel filter. The switch controls the fuel priming pump on the primary fuel filter base.

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The fuel priming pump (1) is located in the primary fuel filter base (3). The secondary fuelfilter base (2) contains the fuel system sensors.

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Located on the top of the secondary fuel filter base are the fuel pressure differential switch (1),and the fuel temperature sensor (2).

The fuel filter pressure differential switch (1) monitors the difference between the outlet fuelpressure and the inlet fuel pressure. A fuel pressure difference exceeding 750 kPa (110 psi)will initiate a Level 1 Warning. If repairs are not made after 4 hours, the engine ECM initiatesa Level 2 Warning and engine performance is decreased.

The status of the sensors and the filter pressure differential switch may be viewed while usingCat ET.

The Engine ECM uses readings from the fuel temperature sensor (2) to make corrections to thefuel rate and maintain power regardless of fuel temperature (within certain parameters). Thisfeature is called "Fuel Temperature Compensation."

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This illustration shows components on the left side of engine with the counterweight removed.

- The Fuel Transfer Pump (1) is a gear-type pump that pulls fuel from the fuel tank throughthe primary fuel filter. The fuel then flows through the secondary fuel filter to thecylinder head.

- The Engine Electronic Control Module (ECM) (2). The engine ECM utilizes theAdvanced Diesel Engine Management (ADEM A4) to control the fuel injector solenoidand to monitor fuel injection. The engine ECM is fuel cooled.


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Right Side of Engine

- The Camshaft Speed Timing Sensor (1) determines the No. 1 compression timing prior tothe engine starting.

- The Atmospheric Pressure Sensor (2) is an input to the Engine ECM and is used as areference for air filter restriction. Also, the sensor is used to supply information to theEngine ECM during operation at high altitudes.

- The Intake Manifold Air Pressure Sensor (3) is an input to the Engine ECM to supplyinformation about the air pressure into the intake manifold.

- The Intake Manifold Air Temperature Sensor (4) supplies air temperature data at the airintake manifold to the Engine ECM.

- The Engine Oil pressure Sensor (5) is an input to the Engine ECM to supply aninformation warning for low oil pressure. The engine derates for low oil pressure and alogged event code is recorded. The event code can be read by using Cat ET or the monitor.


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Left Side of Engine

- The Engine Oil Level Sensor (1) is an input to the Engine ECM to supply an informationwarning for low oil level at start-up.

- The Crankshaft speed timing sensor (2) sends a voltage signal to the Machine ECM inorder to determine the engine speed, direction, and timing.


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Front of Engine

- The Engine Coolant Flow Switch (arrow) is mounted in the coolant passage near theengine coolant pump. When the coolant is flowing past the switch the paddle moves andcloses the switch contacts. The Engine ECM alerts the operator when there is no coolantflow while the engine is running. An event code is logged when this occurs.

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- The Crankshaft speed timing sensor (arrow) sends a voltage level, signal to the EngineECM in order to determine the engine speed, direction, and timing.



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HYDRAULIC SYSTEMS

The hydraulic system on the 345D Hydraulic Excavator is operated and controlled by thefollowing five primary systems:

- The main hydraulic system controls the implements, the attachments, the travel circuits,and the swing circuit.

- The pilot hydraulic system supplies oil to the pilot manifold, pilot control valves, swingpark brake solenoid valve, two-speed travel solenoid valve, and the power shift pressurereducing valve (PSPRV). The pilot system serves primarily as a hydraulic control system.

- The separate hydraulically driven cooling system supplies oil to the fan motor in order tocool the hydraulic oil, the engine radiator, the air to air after cooler, and a fuel cooler.

- The return system directs the return oil from the hydraulic system through the slowreturn check valve and the hydraulic oil cooler before it returns to the tank. The casedrain oil from the pumps and motors goes through the case drain filters without goingthrough the slow return check valve and the oil cooler before returning to the tank.

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This illustration shows the complete hydraulic schematic for the 345D. Both joysticks and travel levers are in the STANDBY position with the engine running and the hydraulic actuationlever in the energized position.

The hydraulic system for the 345D has the following major sub-systems:

- fan system

- main hydraulic system

Each system will be discussed in detail later in this presentation.

NOTE: The system will be broken down into sub-systems in the following illustrationsfor easier understanding.

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Power Shift Pressure System

During machine operation, the machine electronic control module (ECM) receives input signalsfrom the following components:

- Engine speed dial

- Engine speed sensor located on the flywheel housing

- Right and left pumps pressure sensors

- Engine ECM

The engine and pump controller (ECM) continually monitors all of the input signals. The inputsignals are processed by the ECM and an output signal is sent to the Power Shift ProportionalReducing Valve (PSPRV). The PSPRV uses the electrical signal from the ECM and pilot pressure to generate the power shift pressure. Equal power shift pressure is directed to eachpump control to assist in controlling the output flows from the pumps. Power shift pressurehelps regulate pump flow to the maximum allowable hydraulic pump output in relation toengine speed.

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Main Hydraulic Pumps

The 345D main hydraulic pump group has two variable displacement piston pumps inside a common housing, in a side-by-side configuration. The pumps are rated at 360 L/min (95 gpm) each. The pumps will be referred to as the right (drive) pump and the left (idler)pump throughout this presentation. The right pump is driven by the engine via an improvedflexible coupling. The left pump is driven by the right pump through a gear train. The numberof teeth on the gear of the right pump is one tooth less than the gear of the left pump in order toreduce harmonics in the hydraulic system. The difference in rotational speed due to the gearinghas no significant impact on the machine performance or flow output. There is an internallymounted centrifugal charge pump.

The pilot pump (1) is mounted on the main hydraulic pump case. The pilot pump draws oilfrom the pump case and sends it to the pilot filter, then to the pilot system.

The power shift proportional reducing solenoid valve (PSPRV) (2) is mounted on the top andfront of the pump case. The PSPRV uses pilot oil as a control signal to the pumps. Power shiftpressure can be checked at tap (3).

The pump regulators are mounted on top of the pump case. Each rotating group has its ownregulator. The regulators are used to regulate the output flow of the pumps based upon flowdemands.

The left pumps each have their own output pressure taps. Pressure sensors for each pump arelocated directly behind the output pressure taps.

Two case drain filters are located behind the pilot filter.

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The output signal from the machine electronic control module to the PSPRV will change whenthe machine electronic control module detects a change in engine speed. The power shift pressure will change in order to regulate the maximum allowable hydraulic pump output.When the hydraulic pump output is controlled, the desired engine speed is maintained.

When the engine speed increases above the full load setting, due to decreased hydraulichorsepower demand, the power shift pressure will decrease in order to allow more pump flow.A decrease in power shift pressure causes the swashplate to increase its angle, or as it is morecommonly known, to upstroke. If both pumps are in operation at the same time, this conditionoccurs simultaneously in both pumps, and the maximum allowable hydraulic flow output isincreased.

If the engine speed decreases below the full load setting due to hydraulic horsepower exceedingengine horsepower, the power shift pressure will increase in order to regulate output to a levelthat maximizes flow output. As the power shift pressure decreases, the angle of the swashplatein the front pump and rear pump will decrease, or as it is commonly known, will destroke thepump. The maximum allowable hydraulic flow output is optimized to the engine speed.

If flow from only one pump is demanded, the power shift pressure is greatly reduced so the onepump can use full engine horsepower. If flow from both pumps is demanded, the power shiftpressure increases so both pumps can be loaded equally.

40

Each pump receives four different signals to control the output flow of the pumps:

- Power shift pressure- System pressure from that pump - Cross-sensing pressure (from the other pump)- Negative flow control pressure

Power Shift Pressure

The PSPRV receives a control signal from the ECM. The ECM sends an electrical signal to thePSPRV to regulate power shift pressure in relation to the engine speed.

The power shift signal to the pump regulators enable the machine to maintain the target enginespeed for maximum productivity.


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If the engine and pump control senses that the engine is below the target speed due to a highhydraulic load from the main pumps, the controller will increase the power shift pressure. (Thetarget speed is the speed the ECM reads through the engine speed sensor. The reading is taken2.5 seconds after the implement/swing and the travel pressure switches open when the joysticksand the travel control pilot controls are returned to NEUTRAL). As power shift pressureincreases, the regulators destroke the main pumps accordingly. This reduces the load on theengine, and consequently enables the engine to maintain the target engine speed.

If the engine speed is above the target speed, the ECM will decrease power shift pressure, causing the pumps to upstroke and produce more flow.

Cross-sensing Control

Each pump regulator gets a cross-sensing control from the other pump system pressure.

Negative Flow Control (NFC)

NFC is the primary controlling signal for the main pump output. The NFC signal to the mainpump regulator is generated in the main control valve group. The NFC signal is delivered tothe left and right pump regulators from the left and right halves of the main control valvegroup, respectively.

When the joysticks or travel levers are in the NEUTRAL position, the oil flows from the mainpumps through the open center bypass passages of the control valves. The oil flows to thevalves and returns to the tank by way of the NFC control orifices. The restriction of the NFCorifices causes a pressure signal to be sent to the right and left pump regulators, respectively, asan NFC signal.

When the main pump regulators receive a high NFC signal from the main control valves, thepumps remain at a standby output flow at or near minimum pump displacement.

When a joystick or travel lever is moved from a NEUTRAL position, the open-center passageof the corresponding implement/travel function is closed in proportion to spool movement.This reduces the NFC signal to the main pump regulator and the pump output flow is increasedproportionally. When the control valve is fully shifted, then NFC pressure is reduced to slowreturn check valve pressure.

The use of an NFC hydraulic system maximizes efficiency of the machine by only producingflow from the pumps when the flow is needed.

NOTE: A high NFC signal will always overcomes the horsepower control and decreasepump flow to minimum.


41

This illustration shows the pumps in STANDBY condition. Each pump regulator senses theNegative Flow Control (NFC) signal, the power shift pressure, the cross sensing pressure, andthe system pressure for that pump. The regulator will upstroke or destroke the pumps to maintain the pump flow depending on the conditions the regulator senses.

The regulator controls oil pressure to the right side of the actuator. This controls the angle ofthe pump swashplate.

The left pump supplies oil to the following valves:

- straight travel valve- left travel control valve- swing control valve- stick I control valve- boom II control valve- right pump negative flow control valve

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The right pump supplies oil to the following valves:

- straight travel valve- right travel control valve- standard attachment control valve- bucket control valve- boom I control valve- stick II control valve- left pump negative flow control valve.



42

Pump Controls

This illustration shows the three separate control sections of the pump control group.Individual parts are also shown. The three control sections are connected with a series of pinsand linkages. The separate control sections work together to regulate pump flow according todemand and hydraulic horsepower requirements. The separate control sections direct systempressure to and from the minimum angle end (large actuator piston) of the servo piston. Theservo piston moves the swashplate for increased or decreased pump flow. The lower end of thefeedback lever is connected to the servo piston. The feedback lever works as a follow-uplinkage to move the horsepower control spool when the servo piston moves.

The negative flow control (NFC) section works in conjunction with the horsepower controlsection to destroke the swashplate when all hydraulic controls are in NEUTRAL or during implement or travel MODULATION. The torque control section works in conjunction with thehorsepower control section to regulate pump flow while the hydraulic circuits are actuated.

Full pump system pressure is directed to the maximum angle (small) servo piston to upstrokethe pump. A regulated pressure signal is directed to the minimum angle (large) servo piston todestroke the pump.

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This illustration shows an end sectional view of the pump controls. The NFC spool isconnected to the lower end of the NFC lever with a pin. The upper end of the NFC lever pivotson a fixed pin in the housing. The torque control rod is connected to the lower end of thetorque control lever with a pin. The upper end of the torque control lever pivots on a fixed pinin the housing. The upper end of the feedback lever is connected to the horsepower controlspool with a pin. The lower end of the feedback lever is connected to the servo piston.

The feedback lever pin fits tightly into the feedback lever. The feedback lever pin extends intolarge holes in the torque control lever and the NFC lever. The large holes permit individualcontrol from the torque control lever and the NFC lever. Movement of the servo piston causesthe feedback lever to pivot on the feedback lever pin and move the horsepower control spool.


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This illustration shows the components of a pump control group. The NFC spool (1) is connected to the horsepower control spool (2) by the NFC lever (3), the feedback lever pin andthe feedback lever (4). The lower end of the feedback lever is connected to the servo piston (5). Movement of the servo piston moves the lower end of the feedback lever. Theservo piston is also connected to the pump swashplate.

The torque control piston (6) is connected to the feedback lever with the torque control rod (7),the torque control lever (8), and a pin. The NFC lever and the torque control lever operate independently.

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This illustration shows the NFC portion of the pump controls. When all hydraulic controlvalves are in NEUTRAL, a high NFC pressure is directed to the left end of the NFC spool. TheNFC pressure pushes the NFC spool to the right against the spring force. The NFC adjustingscrew changes the effect of the NFC pressure on the NFC spool. Turning the screw in(clockwise) causes the NFC pressure to increase higher before the NFC spool moves. Thiscondition causes the pump to upstroke sooner (less modulation) when the hydraulic controlvalve is ACTIVATED.

Turning the screw out (counterclockwise) causes the NFC spool to move at a lower NFCpressure. This condition causes the pump to upstroke later (more modulation) when thehydraulic control valve is ACTIVATED.

In the STANDBY condition, the horsepower control spool directs a signal pressure, which ispart of system pressure, to the minimum angle end of the servo piston. The increase in pressuremoves the servo piston to the right against the minimum angle stop screw. The pump flow willremain constant until the NFC pressure from the control valve decreases.


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This illustration shows the pump controls at the beginning of an upstroke that was caused by adecrease in NFC pressure. When a hydraulic control valve in the main control valve is shifted,the NFC pressure is decreased. Due to reduced NFC pressure, spring force moves the NFC piston to the left. The NFC piston moves the lower end of the NFC lever to the left with thepin on the upper end of the NFC lever as the pivot point.

As the lower end of the NFC lever moves to the left, the large hole through the lever alsomoves to the left. As the large hole moves to the left, spring force pulls the horsepower controlspool and the upper end of the feedback lever to the left because the feedback lever pin isallowed to move to the left.

The minimum angle servo piston is opened to case drain through the right orifice in thehorsepower control sleeve and the right end of the horsepower control spool. System pressure pushes the maximum angle servo piston to the left to upstroke the pump.


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As the servo piston moves, the lower end of the feedback lever moves to the left. The feedbacklever rotates clockwise with the feedback lever pin as the pivot point. The upper end of thefeedback lever pulls the horsepower control spool to the right until the right land on thehorsepower control spool reaches a balance point between the orifices through the horsepowercontrol sleeve. Flow to and from the minimum angle piston is metered by the horsepowercontrol spool and the horsepower control sleeve. The swashplate angle remains constant untilthe NFC pressure is again changed.

The amount of reduction in NFC signal pressure determines the amount of pump upstroke. IfNFC pressure is reduced to minimum, the pump will upstroke until the servo piston contactsthe maximum angle stop screw.

A decrease in power shift pressure will cause an increase in flow from the pump in the samemanner as described for a decrease in system pressure, since both power shift pressure and system pressures act on the torque control piston.

47

Pump Flow Decrease - Due To Increased Pump Load

This illustration shows the torque control piston and horsepower control spool with the pump inthe upstroked position at the beginning of DESTROKE. For the purpose of this presentation, itis assumed that power shift pressure remains constant.

- Power shift pressure from the PRV enters the pump controls and pushes on the plug at theleft end of the torque control piston.

- System pressure from this pump enters the pump controls and goes to the right shoulderarea on the torque control piston.

- The cross-sensing signal pressure from the other pump goes to the left shoulder area onthe torque control piston.

- The combination of power shift pressure and the two system pressures push the torquecontrol piston to the right against the force of the horsepower control adjustment spring.

- The horsepower control spool directs the signal pressure to the minimum angle end of theservo piston to destroke the hydraulic pump.


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The large horsepower adjustment screw regulates the pressure or point that the pump starts todestroke (large spring adjustment). The small adjustment screw regulates the rate that thepump destrokes (small spring adjustment).

The following occurs when the system pressures and power shift pressure push the torquecontrol piston to the right:

- The torque control rod moves to the right to compress the horsepower control springs.

- The torque control rod moves the lower end of the torque control lever to the right withthe fixed pin on the upper end of the torque control lever as the pivot point.

- The torque control lever pulls the feedback lever pin and the upper end of the feed backlever to the right.

- The feedback lever pulls the horsepower control spool to the right against the springforce.

- System pressure is directed around the horsepower control spool through the centerorifice of the horsepower control sleeve and to the minimum angle end of the servopiston.

- The increase in pressure in the minimum angle piston moves the servo piston to destrokethe pump.

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This illustration shows the pump controls at the end of DESTROKE. When the servo pistonmoves toward minimum angle, the lower end of the feedback lever moves to the right turningthe lever counterclockwise with the feedback lever pin as the pivot point. The lever movementshifts the horsepower control spool to the left so system pressure is metered through the twoorifices to and from the minimum angle end of the servo piston. Pump flow is held constantuntil one of the signal pressures changes.

An increase in power shift pressure will cause a decrease in flow from the pump in the samemanner as described for an increase in system pressure since both the power shift pressure andsystem pressure act on the torque control piston.


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Pilot Hydraulic System

The pilot hydraulic system receives oil from the pilot pump. Oil from the pilot pump is sent tothe pilot manifold and then to the pilot control valves, which are actuated by the joysticks in theoperator's compartment, for machine operation (implement operation, swing operation, andtravel operation). The pilot control valves control the pilot oil pressure to the individual spoolsin the main control valve. When the main control valve spools shift, supply oil from the mainpump is sent to the corresponding cylinders and motors.

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The pilot pump (1) is a gear-type pump that supplies oil flow to the pilot system. The pilotpump is mechanically connected to the left main pump.

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The pilot hydraulic oil filter (4) is located in the pump compartment on the right rear side of themachine. The oil filter is a spin-on type filter.

Oil flows from the pilot pump, through the filter, to the pilot manifold, the power shift pressurereducing valve, and the pilot accumulator. The filter element removes the contaminants fromthe pilot oil.

Contaminated oil or cold oil may cause the oil flow through the filter element to becomerestricted. If the oil flow through the filter element does become restricted, the oil bypasses thefilter element through the bypass valve.

Pilot system pressure can be checked at pressure tap (3). Pilot system pressure can be adjustedat pilot relief valve (1).

The blue dust cap (2) is where the hydraulic system S•O•S can be sampled.

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The pilot relief valve limits the pilot pressure in the pilot system. When the pressure in thepilot system reaches the pressure setting of the pilot relief valve, part of the pilot oil flow isreturned to the hydraulic tank. The pilot relief valve is adjustable.


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The hydraulic pilot oil manifold is accessible by removing the cover plate located under themachine, behind the swing bearing. The hydraulic pilot oil manifold consists of the followingcomponents:

- Hydraulic oil pilot manifold (1)

- Hydraulic activation solenoid valve (2)

- Swing parking brake solenoid (3)

- Two-speed travel solenoid (4)

The hydraulic activation valve is not visible but is located between the hydraulic activationsolenoid valve and the swing brake solenoid. The hydraulic pilot oil accumulator is located onthe top of the mounting bracket for the pilot oil manifold.

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54

Hydraulic Activation Control Lever

The hydraulic activation control lever is located on the left side of the operator's seat. Mountedto a bracket with the hydraulic activation control lever is the limit switch and plunger. Thelimit switch is activated by the hydraulic activation control lever. The limit switch activates theneutral start relay and allows the machine to be started when in the locked position. Withoutthe hydraulic activation control lever in the locked position the machine cannot be started.

After the machine has been started the hydraulic activation control lever must be put into theunlock position in order to supply pilot oil to the pilot control valves.

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When the hydraulic activation control lever is shifted to the LOCKED position, the hydraulicactivation solenoid valve located in the pilot manifold is DE-ENERGIZED. Spring force pushes the hydraulic solenoid up, blocking pilot oil and causing the top side of the hydraulicactivation valve to be open to drain. Spring force pushes the hydraulic activation valve up,causing the pilot joystick to be open to drain. Because there is no pilot pressure available at thepilot control valves, the spools cannot be shifted in the main control valve.

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When the hydraulic activation control lever is shifted to the UNLOCKED position, thehydraulic activation solenoid valve located in the pilot manifold is ENERGIZED. Because thesolenoid valve is now open, pilot oil flows to the hydraulic activation valve. The hydraulicvalve pushes downward against the spring opening a passage which enables pilot oil to flowthrough the hydraulic valve and to the pilot control valves.

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Pilot oil flows from the pilot manifold to the swing parking brake solenoid valve. When theimplement controls and/or swing control levers are operated, the increase in pilot oil pressurecauses the swing/implement pressure switch to close. The swing/implement pressure switch isan input to the ECM. The ECM then signals the swing brake solenoid to actuate. Pilot oil thenflows through the solenoid valve to the swing parking brake located in each swing motor. Thisoil releases the swing parking brakes.


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Two-Speed Travel Solenoid

When the switch for two-speed travel speed is set in the AUTO position, the ECM energizes the two-speed travel speed solenoid valve. With the travel speed solenoid valve energized, a path opens for pilot oil to flow to the displacement change valve in the right travelmotor and left travel motor. As the displacement change valve operates, the travel speed ismaintained at the HIGH SPEED position. In this position, the pressure sensor for main pumpdelivery pressure controls the travel speed in accordance with the travel load. For example, lowspeed during a high load, high pump output pressure condition, and high speed during a lowload and low pump output pressure condition.


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The hydraulic pilot oil accumulator (arrow) stores pilot pressure for use at the main controlvalve. During multiple implement, swing, and travel operations, the pilot system needs moreoil to operate smoothly. The pilot oil accumulator provides additional pilot oil to the pilotsystem when the pilot pump flow is inadequate.

In the accumulator, an internal bladder is filled with nitrogen gas. When pilot oil enters theaccumulator, it acts against the nitrogen gas filled bladder compressing it. There is a checkvalve located inside the hydraulic pilot oil manifold that prevents a backflow of the stored oil inthe accumulator.

The stored hydraulic pressure in the accumulator can also be used to lower the boom and/orstick if the engine is stopped. See the Operation and Maintenance Manual for the correct procedures to lower the boom with a stopped engine.

59

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Pilot Logic Network

The pilot logic network consists of two individual flow paths. An orifice in each flow path allows a small amount of pilot oil flow to enter the paths. Down stream of one orifice, the flowgoes through both travel control valves, only, before returning to the tank. Down stream of theother orifice, the flow goes through each implement and swing control valve before returning tothe tank. The orifices maintain pilot pressure upstream and limit the amount of flow throughthem.

When one or more travel controls are activated, the open-center oil path to tank is blocked.With no open flow path to tank, pressure increases in that part of the pilot logic network. Theincrease in pressure closes the travel pressure switch to signal the ECM to activate the AESC toincrease engine speed.

When one or more implement or swing control valves are activated, the open-center oil paththrough the other orifice to tanks is blocked. With no open flow path to tank, pressure increasesin that part of the pilot logic network. The increase in pressure closes the swing/implementpressure switch to signal the ECM to activate the AESC to increase engine speed. The ECMalso activates the swing park brake solenoid to release the swing park brake. The swing parkbrake is not released when only the travel circuits are activated.


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Straight Travel Mode

When both travel circuits and at least one implement or swing control valve are activated at thesame time, the machine goes into the straight travel mode. Pilot pressure in the pilot logic network, downstream of the implement/swing orifice, goes through the left travel control valveand the right travel control valve and is directed to the top of the straight travel valve. The pilotpressure pushes the straight travel valve down. The machine goes into the straight travel mode.

In the straight travel mode, the right pump flow is directed to the right travel control valve. Theright pump flow also goes through the upper portion of the straight travel valve to the left travelcontrol valve. The left pump flow goes through the left side parallel feeder path to the swingand stick control valve. The left pump flow also goes through the straight travel control valveand into the right side parallel feeder path to the attachment, bucket, and boom control valves.

A check valve and orifice inside the straight travel valve will let some of the left pump flowinto the travel circuits if the right pump system pressure is higher than the travel pressure. Thecheck valve prevents any right pump flow from going to the implement/swing circuits.


62

Pilot Control Valve

The individual pilot control valves in the main pilot control valves are pressure reducing valves.When the joystick is moved, the metering spring pushes the spool down. Pilot oil from thepilot supply port flows around the spool to port (B). The same pressure flows through thecenter of the spool to the lower end of the spool. As pressure increases, the spool moves up tocompress the metering spring. The pilot pressure and flow are metered by the spool until thejoystick is moved farther.

When either joystick is operated, the pilot control valve sends pilot pump oil through the pilotlines to the pilot ports at the main control valve in order to shift the spools of the main controlvalve. This enables the implement operations or swing operation. Return pilot oil from themain control valve returns through the return port of the pilot control valve and is allowed toflow back to the hydraulic tank.

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The amount of pilot oil pressure that flows from the pilot control valve to the main controlvalve directly corresponds with the position of the joystick. When the joystick is movedslightly from the NEUTRAL position, low pilot oil pressure is sent to the spool of the maincontrol valve. The main control valve shifts a slight amount. The volume of oil delivery to thecylinders and/or motors is small. The speed of the cylinders and/or motors is slow. As thejoystick is moved farther from the NEUTRAL position, the pilot oil pressure that is sent to themain control valve increases. The spool in the main control valve shifts farther and the speedof the cylinders and/or motors increases. Thus, cylinder speed and motor speed is controlled bythe amount of movement and the position of the joystick.



63

HYDRAULIC FAN SYSTEM

The fan system is made up of a fan motor and fan pump to cool the hydraulic oil, the engineradiator, the fuel cooler, and the ATAAC.

The fan pump is an electronically controlled, variable displacement, piston pump mounted onthe front of the engine and driven from the timing gears on the engine. The pump output iscontrolled by the angle of the swashplate. The swashplate is then controlled by the engineECM. The hydraulic oil temperature sensor and the engine coolant temperature sensor sends asignal to the Engine ECM. A higher hydraulic oil temperature or coolant temperature willcause a stronger signal to be sent to the fan solenoid in order to increase the speed of the fan formore cooling capacity.

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Hydraulic Fan Pump

The 345D features an electronically controlled, variable displacement, piston pump (1) for thefan circuit. The fan pump is mounted on the left front (counterweight side) of the engine, andis driven though the front gear train. The pump regulator (3) has a proportional solenoid (2)directly mounted on the pump.

The pump output is controlled by the angle of the swashplate. The solenoid controls the angleof the swashplate. The solenoid is then controlled by the Engine ECM. The hydraulic oiltemperature sensor and the engine coolant temperature sensor send a signal to the Engine ECM.A higher hydraulic oil temperature or coolant temperature will cause a lower signal to be sent tothe fan solenoid in order to increase the speed of the fan for more cooling capacity.

The solenoid is calibrated through the monitor or through Cat ET in the fan speed calibrationfunction. Under normal operating conditions, the fan rpm will vary between 600 and 1050 rpm.If the solenoid signal goes to zero, the fan speed will go to a maximum mechanical fan speedthat is governed by a relief valve internal to the pump. Fan rpm will exceed 1050 and pumpdelivery pressure will be approximately 31,000 kPa (4500 psi). Under this default condition,maximum speed will be constant, regardless of coolant and oil temperatures. If there is an opencircuit, an error code will appear on the monitor as well.

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Hydraulic Fan Pump Controls

This illustration is a schematic of the fan system with the fan at maximum controlled pressure,resulting in maximum controlled fan speed.

The hydraulic fan is standard on the 345D Hydraulic Excavator. The fan is part of thehydraulic system, but it is controlled by the engine ECM. The engine ECM considers twoinputs for controlling the fan. The fan is a demand fan. When engine coolant and/or hydraulicoil temperatures are high, the fan runs at a faster speed. If the temperatures are low, the fanspeed is decreased.

The engine coolant temperature sensor provides temperature information to the Engine ECM.The Engine ECM constantly monitors this temperature input. The hydraulic oil temperaturesensor is the second input to the Engine ECM. The Engine ECM constantly monitors this temperature input. Increased fan speed occurs when the hydraulic oil is at higher temperature.

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The Engine ECM monitors the temperature inputs to provide a signal to the (proportional) fanpump pressure control solenoid. Maximum flow is sent to the fan motor, causing the fan toturn at the maximum controlled rpm, when the solenoid receives minimum current from theEngine ECM. Maximum mechanical pump pressure and maximum fan speed (high pressurecut-off) can be achieved by disconnecting the electrical connection to the solenoid or by usingCat ET to turn OFF the fan control (Engine ECM/Configuration screen).

When maximum fan speed is required, the fan pump pressure control solenoid is de-energizedaccording to the temperature input, causing the fan to turn at a faster speed. Maximumcontrolled fan speed is attained when the fan pump pressure control solenoid receives the leastamount of current from the Engine ECM.

If communication is lost between the Engine ECM and the fan pump pressure control solenoid,the fan will default to the maximum mechanical pressure setting (high pressure cutoff). Thisresults in a higher system pressure of approximately 31,000 kPa (4500 psi) and fan speed thanthe maximum controlled pressure and speed.

Cat ET or the monitor can be used to check or calibrate the fan speed. Refer to the 345D Testand Adjust manual for the corrections.



66

This illustration is a schematic of the hydraulic fan system with the fan at minimum speed.

The fan pump pressure control solenoid is energized, causing the fan to turn at a slower speedif maximum fan speed is not required. Minimum fan speed is attained when the fan pump pressure control solenoid is completely energized.

When the fan pump pressure control solenoid is completely energized, the pressure controlspool is unseated by the solenoid, allowing pump system pressure to drain to tank. This actionlowers the pressure in the spring chamber of the pump control spool and the pump controlspool shifts up. Pump flow is then allowed to fill and pressurize the large actuator in the fanpump and the pump destrokes. With the pump destroked, oil flow to the fan motor is reducedand the fan speed is reduced.

The fan will default to the maximum mechanical pressure setting if communication is lostbetween the Engine ECM and the fan pump pressure control solenoid. This results in a fanspeed that is higher than the maximum controlled fan speed.

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67

The engine ECM de-energizes the fan pump pressure control solenoid, sending the least amountof current when conditions require maximum controlled fan speed. (With no current, to thepressure control solenoid, the pump control spool [high pressure cut-off] will limit themaximum pressure and the fan speed to its maximum rpm. This state can be achieved bydisconnecting the fan pump control solenoid or by using Cat ET to turn the fan control OFF.This procedure is required when making adjustments to the fan system pressure settings.)

The pressure control spool spring forces the top half of the pressure control spool up, againstthe solenoid pin and holds the lower land of the upper pressure control spool against the seatwhen the solenoid receives minimum signal. This blocks most of the pump output oil in thepump control spool spring chamber from draining to tank through the case drain passage,which causes the pump control spool spring chamber to become pressurized. The force of thespring at the top of the pump control spool, plus the pressure of the oil, is greater than the oilpressure at the bottom of the pump control spool. The pump control spool is held down,blocking pump output oil from entering the signal passage to the large actuator piston in thepump. The large actuator piston is open to drain and is at tank pressure.

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The bias spring and pump system pressure moves the pump swashplate to an increased angle,which causes the pump to UPSTROKE. This condition provides a controlled maximum flowof oil to the fan motor and creates maximum controlled fan pump system pressure, whichresults in maximum controlled fan speed. If the solenoid fails (no current to the solenoid), thepump goes to maximum displacement.

The mechanical high pressure cutoff is adjusted using the adjustment screw. When theadjustment screw is turned in (clockwise), it increases the force of the pressure control spoolspring, which increases the the pump pressure required to unseat the land of the upper pumpcontrol spool, thereby increasing maximum cut-off pressure.

Maximum cut-off pressure will be lowered when the screw is turned out (counter-clockwise).



68

This illustration shows the fan control valve with the fan pump at minimum displacement.

If the engine coolant or hydraulic oil temperatures are below a certain amount, the engine ECMsends an increased signal to the pressure control solenoid. The solenoid plunger and pin pushthe pressure control spool down. With the pressure control spool pushed down, the springchamber on top of the pump control spool is open to case drain around the seat on the lowerend of the upper pressure control spool. The orifice in the top of the pump control spool creates a pressure increase on the lower end of the pump control spool. The pressure pushesthe pump control spool up until the lower land of the two center lands on the pump controlspool raises above the bottom of the pump control spool.

Pump system pressure flows around the pump control spool and around the lower pressure control to the large actuator piston. The increased pressure in the large actuator piston pushesthe swashplate toward minimum angle. Pump flow decreases and therefore fan speed decreases.

With cold oil or at cold start-ups, the ECM signal to the pressure control solenoid is maximum.Maximum pressure is sent to the large actuator piston. The swashplate moves toward minimum angle until the vent hole through the large actuator piston is open to case drain. Thepump flow is decreased to minimum and the fan speed is also at minimum.

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Hydraulic Fan Motor

The fan motor (arrow) is a fixed-displacement piston motor. Case drain oil from the fan motoris combined with the case drain oil from the swing motors and the travel motors. Case drain oilfrom the motors is sent through the case drain filters and to the hydraulic tank. An internalmakeup valve in the pump is used to supply makeup oil to the motor when flow from the pumpis shut off. The makeup oil allows the motor to get oil when no flow is present in order toprevent the motor from cavitating. The makeup oil prevents cavitation and damage to themotor.

69


70

Main Control Valve

The main hydraulic system is a Negative Flow Control (NFC) system that supplies hydraulicpower at high pressures and high flow rates to perform work. Two main hydraulic pumpssupply oil to the main control valve group. The individual hydraulic circuits are controlled byvalves in the the main control valve group.

The main hydraulic system supplies the following circuits:

- Swing

- Stick

- Travel

- Boom

- Bucket

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The main control valve group is located in the center of the upper structure of the machine.The main control valve group receives pilot oil signals from the operator controls in the cab.Each pilot signal shifts the appropriate control valve in the correct direction. When the valveshifts, oil flows from the main hydraulic pumps to the appropriate hydraulic cylinder orhydraulic motor to perform work. The 345D main control valve is similar to the 345C valve.Major components of the main control valve are:

- Stick 2 Control Valve (1)

- Boom 1 Control Valve (2)

- Bucket Control Valve (3)

- Attachment Control Valve (4)

- Right Travel Control Valve (5)

- Left Travel Control Valve (6)

- Swing Control Valve (7)

- Stick 1 Control Valve (8)

- Boom 2 Control Valve (9)

- Main Relief Valve (10)

- Boom Drift Reduction Valve(11)

- Stick Drift Reduction Valves (12)

71

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- Straight Travel Valve (Not visible, located directly behind the main relief valve)

- Right side Negative Flow Control Valve (13)

- Left Side Negative Flow Control Valve (not shown)


72

This illustration of the main control valve is from the rear of the machine toward the boom.

The main control valve is mounted vertically between the frame rails behind the base of theboom. Flow from the two hydraulic pumps enters the control valve from the rear. Flow fromthe left hydraulic pump flows through the left side of the control valve and flow from the rightpump flows through the right side of the control valve.

The control spools are all open-center control valves. When all control spools are in NEUTRAL, the flow from both pumps goes through the control valve to the negative flow control valves (NFC) (in each end of the control valve). The NFC valves maintain a pressure ineach signal line that goes to each pump regulator when all spools are in NEUTRAL or whenone or more of the spools are partially moved. When a control spool is activated, the open-center passage upstream of the NFC valve is blocked causing a decrease in NFC pressure.

The NFC pressure, when high, is used to fully destroke the hydraulic pumps. When thenegative flow pressure decreases, the pump flow increases.

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The travel pressure switch (1) and the implement/swing pressure switch (2) are on the front sideof the main control valve. The pressure switches are activated by the pilot logic network. Theswitches close at approximately 500 kPa (70 psi) and open at approximately 280 kPa (40 psi).The pressure switches are inputs to the machine ECM. The machine ECM uses these inputs toidentify when a hydraulic function has been activated. When either of the switches are closedthe machine ECM will turn the Automatic Engine Speed Control (AESC) and increase the onetouch low idle back to the current speed dial setting.

When the travel pressure switch is activated the machine ECM will activate the travel alarm.

When the swing/implement pressure switch is activated the machine ECM will send a signal torelease the swing brake.

When both pressure switches are activated, pilot oil will be directed through the pilot logicnetwork to shift the straight travel spool.

NOTE: This picture shows a material handler main control valve. Material handlersare NOT equipped with the heavy lift option. Material handlers will be equipped with astandard main relief valve and plug in the HL pilot port.

73

1 2


The 345D has a two stage main relief valve (arrow). During normal operation the relief valvepressure setting is approximately 35,000 kPa (5050 psi). If the heavy lift function is activated,a pilot pressure signal is directed to the main relief valve. The pilot pressure signal pushes theload piston down to increase the pressure setting of the main relief valve to 38,000 kPa (5500 psi).

During the heavy lift mode the following parameters are:

- Engine rpm range is 1420 - 1600 rpm's.

- Pump hydraulic horsepower is limited to approximately 60% of maximum.

- Main relief pressure is increased to 38,000 kPa (5500 psi).

NOTE: The heavy lift pressure must be set first.

74

75

When the main relief valve is closed, spring force acts on the top end of the poppet to keep itseated. Hydraulic oil flows through the orifice in the dump valve and pressure builds in thespring chamber on the top of the dump valve. The pressure and spring force keeps the dumpvalve seated.

When hydraulic pressure builds to the main relief setting, the poppet moves up against the forceof the upper spring. The hydraulic oil in the dump valve spring chamber will flow past thepoppet and return to tank. This will cause a large pressure difference to form across the orifice.Because the system pressure is higher on the bottom side of the orifice, it will cause the dumpvalve to shift up, allowing high pressure oil to be returned to the tank.

When the heavy lift solenoid is activated a pilot signal is directed to the top of the inner spoolto shift the spool down to the stop. Shifting the inner spool down increases the spring force onthe poppet.


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76

The line relief valves work the same as the main relief valve but are only a single stage relief.The line relief valves receive no pilot signal from the heavy lift solenoid as does the main reliefvalve.

When needed, the line relief valves act as makeup valves. In this situation tank pressure ishigher than circuit pressure. Tank pressure will act on the shoulders of the outer spool, whichwill be greater than circuit pressure plus spring force in the spring chamber. This will cause theouter spool to shift up, allowing oil to flow from the tank into the circuit as makeup oil.


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77

Bucket Hydraulic Circuit

When the right joystick is moved for the BUCKET CLOSE operation, pilot oil flows throughthe pilot control valve and pilot lines to the top of the bucket control valve. The pilot oilpressure shifts the bucket control spool down. The decrease in NFC pressure, resulting fromthe shifted bucket control spool, causes the right pump to UPSTROKE.

Oil from the right pump flows through the parallel feeder passage to the bucket control valveand to the head end of the bucket cylinder to close the bucket. Return oil from the rod end ofthe bucket cylinder returns through the bucket control spool back to tank.

When the bucket control spool is shifted down, the pilot oil flowing to the drain through thepilot logic network passage is blocked. Pilot oil pressure will now build on the downstreamside of the implement/swing orifice, causing the implement/swing pressure switch to close. Theclosed pressure switch will cause the machine ECM to actuate the automatic engine speedcontrol (AEC) to increase engine speed and release the swing brake.

NOTE: To prevent the bucket from closing too fast, an orifice in the bucket controlvalve slows the cylinder rod end oil return to tank.

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The BUCKET OPEN operation is similar to the BUCKET CLOSE operation.

When the right joystick is moved for the BUCKET OPEN operation, pilot oil flows through thepilot control valve and pilot lines to the bucket control valve. The pilot oil pressure shifts thebucket control spool up and allows right pump oil to flow through the bucket control valve tothe rod end of the bucket cylinder to open the bucket. Return oil from the head end of thebucket cylinder returns through the bucket control valve back to tank.


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79

Boom Hydraulic Circuit

When the right joystick is moved for the BOOM UP operation, pilot oil flows through the pilotcontrol valve and pilot lines to the boom I control valve and the boom II control valve. Thepilot oil pressure at approximately 700 kPa (100 psi) shifts the boom I spool down. Oil fromthe right pump flows through the parallel feeder passage to the head end of the boom cylindersto raise the boom.

When boom pilot activation pressure increases to more than approximately 1100 kPa (160 psi)the boom II spool starts shifting down. Oil flow from the left pump flows through the parallelfeeder path. Left pump flow through the boom II spool flows through an external line tocombine with right pump flow outside of the main control valve. This combined oil flows gothe head end of the boom cylinder.

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The BOOM LOWER operation is similar to the BOOM UP operation.

When the right joystick is actuated for the BOOM LOWER operation, pilot oil flows throughthe pilot control valve and pilot lines to the boom I control valve. The pilot oil pressure shiftsthe boom I control spool up and allows right pump oil to flow through the boom I control valveto the rod end of the boom cylinders to lower the boom. Pilot oil also shifts the boom loweringcontrol valve to allow return oil from the head end of the boom cylinders to return to tank. Forthe boom lower operation only one pump flow is needed. Left pump flow is used to lower theboom.

Return oil from the head end of the boom cylinders returns through the boom lowering controlvalve, the boom I control valve, and back to tank.

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81

Boom Down with Regeneration

Boom LOWER is a one pump flow operation. During fast boom lower, a portion of the boomcylinder head end oil combined with the left pump flow. The combined flows are directed tothe rod end of the boom cylinders.

Boom lower pilot pressure shifts the boom I control valve up. The open center section of thecontrol valve is not completely blocked. A portion of the pump flow goes to the right side NFCvalve. A higher NFC pressure keeps the pump only slightly upstroked. The lower section ofthe boom I control valve directs pump flow to the rod end of the cylinders.

Return oil from the head end of the boom cylinders goes through an orifice before returning tothe tank. The orifice creates a back pressure in the control valve. The head end oil flowsthrough the regeneration check valve to combine with pump flow to the rod end of the cylinders.

The combined flows permit fast boom lower operation with reduced horsepower requirements.

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82

Boom Drift Reduction Valve

The boom drift reduction valve prevents the boom from drifting down due to normal leakagewhen the hydraulic control valve is in NEUTRAL or HOLD.

Pressure in the head end of the boom cylinders is higher than the pressure in the boom controlvalves. The boom cylinder head end is connected to the spring side of the check valve throughthe blocker valve. The boom cylinder head end pressure combines with the spring force tokeep the boom drift reduction valve closed. The closed boom drift reduction valve prevents theboom cylinder from drifting down.


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83

A pilot signal is sent to the bottom of the Boom I control valve and to the top of the blockervalve of the boom drift reduction valve. A pilot signal is also sent to the top of the blockervalve of the boom drift reduction valve. The blocker valve shifts down allowing trapped oil inthe spring side of the check valve to be released to tank. The check valve will be forced off theseat of the drift reduction valve by the return oil from the head end of the boom cylinder. Theoil returns to tank through the boom drift reduction valve and the Boom I control valve.

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84

Boom Lowering Control Valve

Some machines are equipped with boom lowering control valves (BLCVs) instead of a boomdrift reduction valve. The BLCVs ensure that if the boom is raised above the ground and ahydraulic hose breaks, the boom will not fall. Return oil from the head end of the boomcylinders is restricted or blocked from flowing back to tank.

During a boom raise operation, system oil flows through the BOOM I and BOOM II controlvalves and the BLCVs to the head end of the boom cylinders. Oil that flows through theBLCVs flows over a check valve in the BLCVs unrestricted and raises the boom cylinders.The rod end oil flows through the BOOM I valve back to tank.

The oil flows though the boom lowering control valves during BOOM UP unrestricted.

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85

During a boom down operation the head end oil must pass through the BLCVs and back totank.

The pilot signal that shifts the BOOM I spool for boom lower operation is also directed to theblocking valve inside the BLCVs. The pilot pressure shifts the blocking valves to the leftallowing the head end oil to return through an orifice and to tank. Without the blocking valvesshifted to the left, the return oil path is blocked and the oil cannot flow through the valve backto tank. Spring force shifts the valve back to the blocked position without the pilot signal.

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86

Boom Priority

During Boom Priority, a pilot signal from the boom pilot control valve is sent to the boompriority valve, which restricts the pilot signal from the stick pilot control valve to the bottom ofthe Stick II control valve. The STICK II spool will not shift. No oil flow from the right pumpwill be directed to the stick.

The Boom II control valve is getting a signal on the top side from the boom pilot valve and thebottom side from the stick pilot control valve. This leaves the Boom II control valve centeredand allows no flow from the left pump to go to the Boom Circuit.

The right pump upstrokes sending all right pump flow through the BOOM I control valve to theboom cylinders. The left pump upstrokes and sends all the left pump flow through the Stick Icontrol valve to the stick cylinders.

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The boom priority pressure reducing valve is located behind the swing bearing on the left sideof the machine. The boom priority PRV provides boom up priority over the stick in function.

87


88

During STICK IN, the pilot oil from the joystick flows to the stick 1 valve. The pilot oil alsoflows around the shoulders of the boom pressure reducing valve to the stick 2 spool in the maincontrol valve group. When there is no BOOM UP pilot oil present, the stick 2 valve receivesfull pilot oil.

During BOOM UP functions, a portion of the BOOM UP pilot oil is diverted to the boom andswing priority pressure reducing valve. BOOM UP pilot oil acts on the shoulders of the boompressure reducing valve, causing it to shift downward against spring force.

When BOOM UP and STICK IN are operating at the same time, the amount of STICK IN pilotoil available to the stick 2 valve will vary according to the amount of BOOM UP pilot oil at theboom priority pressure reducing valve. As BOOM UP pilot pressure increases, stick 2 pilotpressure decreases.

As pilot pressure to stick 2 decreases, the stick 2 spool moves toward NEUTRAL, limiting flowto stick 2 and giving priority to the boom circuit.


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89

Stick Hydraulic Circuit

When the left joystick is actuated for the STICK OUT operation, pilot oil flows through thepilot control valve and pilot lines to the stick I control valve and the stick II control valve. Thepilot oil pressure at approximately 700 kPa (100 psi) begins to shift the stick I spool down. Oilfrom the left pump flows through the left parallel feeder passage to the rod end of the stickcylinders to extend the stick.

When stick pilot activation pressure increases to more than approximately 1100 kPa (160 psi),the stick II spool begins shifting down. Oil flow from the right pump flows through the parallelfeeder path, in the right side of the main control valve, and the top of the stick II spool. Rightpump flow through the stick II spool goes through an external line to combine with left pumpflow upstream of the stick I spool. This combined oil then flows to the rod end of the stickcylinders.

Return oil from the head end of the stick cylinder returns through the stick I control valve andback to tank.

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90

The STICK IN operation is similar to the STICK OUT operation.

When the left joystick is actuated for the STICK IN operation, pilot oil flows through the pilotcontrol valve and pilot lines to the stick I control valve and the stick II control valve. The pilotpressure also goes to the blocker valve in the stick drift reduction valve. The pilot oil pressureat approximately 700 kPa (100 psi) begins to shift the stick I spool up and shifts the blockervalve down. Oil from the left pump flows through the left parallel feeder passage, through thestick I spool, and to the head end of the stick cylinder to retract the stick.

Return oil from the rod end of the stick cylinder returns through the stick drift reduction valve.The blocker valve receives a pilot signal from the stick joystick and shifts the blocker valvedown allowing the oil behind the check valve to return to tank. The return oil from the rod endof the stick cylinder unseats the check valve and flows past the check valve, to the Stick Icontrol valve and back to tank.

When stick pilot activation pressure increases to more than approximately 1100 kPa (160 psi)the stick II spool starts shifting up. Oil flow from the right pump flows through the rightparallel feeder path, and to the stick II spool. Right pump flow through the stick II spool flowsthrough an external line to combine with left pump flow upstream of the stick I spool. Thecombined flow then flows to the head end of the stick cylinders.

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91

This illustration shows the stick 1 control valve in the HOLD position. The left hydraulic pumpsupplies flow to the stick 1 control valve.

Left pump pressure flows through the center bypass passage and back to tank while in the holdposition. The parallel feeder path and the return lines are both blocked in the center position.


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92

When the stick pilot control valve is moved to the STICK OUT position, pilot pressure isdirected to the top of the stick I control valve. Pilot pressure shifts the stick I control valvedown, blocking the pilot logic network. With the pilot logic network blocked, theimplement/swing pressure switch is activated.

The stick I control spool shifts down, partially blocking oil flow through the center bypass passage. When flow through the center bypass passage is decreased, the NFC signal pressure tothe left pump regulator group is decreased. The decrease in NFC pressure causes the left pumpto upstroke, increasing pump flow.

With the center bypass passage blocked, oil from the parallel feeder passage is allowed to flowthrough the stick I control valve, out to the rod end of the stick cylinder, in order to extend thestick.


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93

Stick Regeneration

The stick regeneration valve transfers stick cylinder rod end oil to the head end of the stickcylinder. The rod end oil combines with pump flow to prevent cavitation of the stick cylinderduring fast stick in. The extra oil prevents the stick "Tail Wag" while the pump flow fills thestick cylinders.

When the left joystick is moved to the STICK IN position, pilot pressure goes to the bottomend of the stick I and stick II valves. The pilot pressure also goes to the top end of the stickdrift reduction valve and to the stick regeneration valve. The pilot pressure shifts the stick Iand the stick II valves up to allow pump oil to flow to the head end of the stick cylinder. Thestick drift reduction blocker valve and the regeneration valve are both shifted down.

When the stick drift reduction blocker valve moves down, the spring chamber at the left of thedrift reduction check valve is open to drain. Pressure in the rod end of the stick cylinder pusheson the shoulder area of the check valve and lifts the valve off its seat. The stick rod end oilflows around the drift reduction check valve to the stick 1 control valve. The throttling slots inthe stick 1 valve direct part of the stick cylinder rod end oil to the tank.

If the system pressure in the head end of the stick cylinder is less than 15700 kPa (2300 psi),the stick regeneration valve directs the majority of the rod end oil to combine with pump flowgoing to the head end.

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When the STICK IN system pressure is more than 15700 kPa (2300 psi) the stick regenerationunloading valve opens to permit part of the stick rod end oil to return to the tank without goingthrough the throttling slots in the stick I valve. The unloading valve reduces the back pressurein the rod end of the stick cylinder while digging.

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95

Stick Drift Reduction Valve

This visual shows the stick drift reduction valve with the stick hydraulic control valve inHOLD, the stick extended, and the bucket off the ground. The stick drift reduction valveworks similarly to the boom drift reduction valve. The stick drift reduction valve holds the oilin the rod end of the stick cylinder. The boom drift reduction valve holds the oil in the headend of the boom cylinders.

The stick cylinder has a residual pressure in the rod end. The pressure in the stick cylinderenters the stick drift reduction valve at the top. Spring force pushes the stick drift reductioncheck valve against the seat. The check valve prevents the stick cylinder rod end pressure fromgoing to the stick hydraulic control valve. The stick residual pressure is directed through theblocker valve to the spring chamber of the stick drift reduction valve. Therefore, the stickresidual pressure helps the spring force keep the stick drift reduction valve closed and preventsthe stick from drifting.

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During STICK IN operation, pilot pressure is directed to the bottom of the stick I valve and tothe top of the blocker valve. Pilot pressure shifts the blocker valve down against the springforce. The spring chamber of the stick drift reduction check valve is vented to drain throughthe blocker valve. Pressure in the rod end of the stick cylinder pushes on the shoulder area ofthe stick check valve and shifts the valve to the left allowing the stick cylinder rod end oil toflow to the control valve.


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Swing Hydraulic System

The 345D has two swing motors (1) and two separate double reduction planetary swing drivesthat are directly in front of the main control valve.

97


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98

When the left joystick is actuated for the SWING LEFT operation, pilot oil flows from theswing pilot control valve and pilot lines to the bottom of the swing control valve. Pilot pressurein the pilot logic network increases. The ECM turns the swing park brake solenoid on torelease the swing park brakes. The pilot oil pressure shifts the swing control spool up blockingthe center bypass passage. The decrease in NFC pressure, resulting from the shifted swingcontrol spool, causes the left pump to UPSTROKE.

Oil flow from the left pump flows through the parallel feeder passage of the swing controlvalve to the left side of the swing motors to rotate the upper structure of the machine to the left.Return oil from the right side of the swing motors returns through the swing control spool backto tank.

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99

Swing Right Without Priority

The swing priority valve provides a swing priority function over the STICK IN and STICKOUT function when the SWING function is activated at the same time as a STICK function.

During light swing conditions, pilot oil from the pilot manifold goes through the swing priorityvalve. The pilot oil flows through the swing priority valve unrestricted. The pilot oil shifts theunload valve to the right and allows the trapped oil behind the parallel tandem logic (PTL)valve to drain to tank. Left pump flow is allowed to flow over the check valve to the stick Ispool for use in the STICK OUT or STICK IN functions.

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100

The swing priority valve provides swing priority over the STICK IN and STICK OUT functionswhen swing is activated at the same time as the stick.

When the swing priority is not active, full pilot signal flows through the swing priority pressurereducing valve and to the parallel tandem logic valve. The pilot signal pushes the paralleltandem logic valve over against the force of the spring. This will allow the stick 1 valve tohave full flow from the main pumps.

During slow swing conditions, oil flows from the left pump parallel passage to the parallel tandem logic valve. The oil passes through the parallel tandem logic valve unrestricted andflows to the stick 1 spool for STICK IN or STICK OUT.

When swing is activated, the swing priority valve receives a swing pilot signal and shifts downproportionally to the amount of swing pilot oil that is supplied. When the swing priority valveis shifted, the oil from the left pump parallel feeder passage is restricted at the parallel tandemlogic valve. The stick 1 valve receives pump supply through an orifice in the parallel tandemlogic valve, reducing the flow sent to the stick control valve. More flow is now available forswing operations to generate higher swing force needed during swing operations, such ascleaning a trench wall.


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The swing priority pressure reducing valve is located behind the swing bearing on the left sideof the machine. The swing priority PRV provides swing priority over the stick functions.

101



102

Swing Right with Priority

During heavy swing conditions with the SWING and the STICK circuits activated, a pilot signal is sent from the swing joystick to the swing priority valve which restricts the pilot flowto the unloading valve. The unload valve is shifted back to the left by spring force. Left pumpsystem pressure flows through the unloader valve to the spring chamber on the PTL valve. ThePTL valve shifts up to block flow in the left side parallel feeder path from going to the stick Ivalve. Left pump flow is isolated for the swing circuit. Left pump oil flows through the swingcontrol valve out to the swing motors.

The parallel tandem logic valve blocks right pump flow from the stick during swing priority. Ifmore stick force is needed, the operator must move the stick joystick farther. The increasedpilot pressure shifts the stick II spool and right pump flow goes through an external hose to thestick I valve. During swing priority, right pump flow goes to the swing circuit and left pumpflow goes to the stick circuit.

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103

Swing Motor

The illustration shows the swing motor and swing motor components in NEUTRAL.

When no implements or swing are activated, the implement/swing pressure switch is open. TheECM turns the swing park brake solenoid valve OFF. The springs in the swing park brakeapply the swing park brake. After the implement/swing operations are stopped, the ECM waits3 to 5 seconds to turn the swing park brake solenoid OFF. The swing stops hydraulically andthen the swing park brake applies.

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104

Swing Parking Brake

The swing park brake is a multiple disc oil-type brake that operates automatically. The swingpark brake is spring applied and hydraulically released. The swing brake consists of five lineddiscs and six steel plates. The discs have internal gear teeth that mesh with gear teeth on theoutside of the swing motor barrel assembly. The steel plates mesh with the swing motor housing.

The swing park brake is released automatically. When pressure increases in the pilot logic system, the swing/implement pressure switch is activated sending a signal to the ECM. TheECM activates the swing brake solenoid valve. The swing brake solenoid valve directs pilotpressure from the pilot manifold to the brake piston. Pilot pressure then moves the brake pistonagainst the spring force to release the brake. The swing brake is released when any hydrauliccontrol other than travel is activated.

The swing park brake is released almost instantly when the hydraulic controls are activated.

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105

Swing Motor Crossover Relief Valve

Each swing motor has two swing crossover relief valves and makeup valves that are similar tothose used in the 320C Hydraulic Excavator. One relief valve is for right swing and the otherrelief valve is for left swing. The swing crossover relief valves also have a "soft swing" controlfeature similar to the 345B. When pump system pressure is directed to the swing motor, thepressure pushes on the end of the swing relief valve. The pressure will open the swing reliefvalve at a relatively low pressure [approximately 7600 to 13000 kPa (1100 to 1900 psi)].

The system pressure also goes through the orifice in the end of the swing crossover relief valveto the cavity between the piston and liner on the right end of the relief valve. As pressureincreases inside the cavity, the pressure pushes the piston to the left increasing the spring force.Approximately one tenth of a second is required for enough oil to flow through the orifice tofill the cavity and move the piston to the limit of its travel.

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The increase in spring force closes the swing relief valve. With the increase in spring force, ahigher system pressure is required to hold the relief valve open.

In other words, the swing crossover relief valve opens at a lower pressure than is needed tohold the valve open. This gradual increase in swing pressure causes a dampening effect onpressure surges.

If an external force causes the upper structure to rotate when the swing control valve is not activated, the swing motor acts like a hydraulic pump and causes an increase in the swing pressure in the swing motor. As pressure increases inside the swing motor, it pushes on the leftend of the relief valve. The relief valve functions the same as described for the increase in system pressure. Oil is circulated inside the swing motor through the swing crossover reliefvalve causing a hydraulic lock inside the motor to slow the upper structure.

As the upper structure continues to rotate, tank pressure pushes the low pressure makeup valveoff its seat and tank oil flows into the motor to prevent cavitation. The makeup valve opensand oil from the makeup port enters the low pressure side of the swing motor.

106

Swing Anti-Reaction Valves

The anti-reaction valves are used to eliminate the reverse swing effect when the swingoperation is stopped. When the swing hydraulic control valve is returned to the NEUTRALposition, the upper structure continues to rotate due to inertia. Without the anti-reaction valves,the swing motor acts like a pump and a hydraulic lock is formed in the swing lines between themotor and the swing control valve. This pressure causes the swing motor to turn the upperstructure in reverse after the upper structure is stopped.

When the swing control valve is returned to NEUTRAL, pressure increases and is directed tothe anti-reaction valves. The anti-reaction valves shift to connect the outlet passage to the inletpassage through the valve allowing pressure oil to move to the low pressure side. As the upperstructure slows to a smooth stop, pressure in the high pressure side decreases, allowing springforce to return the anti-reaction valve to the neutral position.


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107

The anti-reaction valves are designed to minimize movement of the upper structure at the endof swing movement in order to reduce "swing wag." The anti-reaction valves work togetherand act as shock absorbers.

When swing is activated, the anti-reaction valves are in the blocked position.

When the swing operation is activated, system pressure enters the center cavity of the right anti-reaction valve. The pressure pushes the piston down against the plug and pushes theplunger and spool up to compress the springs. System pressure also goes through an internalpassage to the large spring chamber on the left anti-reaction valve. The pressure pushes the leftplunger and spool up to compress the springs.

As the spools and plungers are pushed up, makeup oil from the tank flows through the smallorifices into the chambers below the two spools.

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108

When the swing control valve is returned to the NEUTRAL position, pressure and flow fromthe right pump decreases. When the swing system pressure decreases, the large springs pushthe two plungers down. The oil trapped in the two chambers below the two spools cannotescape fast through the two small orifices. The plungers separate from the spools. The swingpressure in the right side flows through the center of the right spool through an internal passageto the low pressure side of the swing motor. The pressure also flows through an internalpassage to the center of the left anti-reaction valve. The pressure flows up through the center ofthe left spool to the low pressure side of the swing motor. The small springs on top of thespools push the spools down.

As the upper structure continues to swing, due to inertia, the swing motor starts acting like apump. With the return passage through the swing control valve closed, pressure increases inthe left side of the motor. The pressure goes through the center of the left spool and plunger topush the left piston down and the left plunger and spool up. The pressure goes through theinternal passage to the spring chamber at the bottom of the right anti-reaction valve. The pressure pushes the right plunger and spool up. Again, makeup oil is pulled into the chambersbelow the two spools.

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When the upper structure stops, the pressure decreases and the large springs push the plungersdown separating the plungers from the two spools. The pressure flows through the center ofthe left spool and the internal passage to the low pressure side of the swing motor. The pressure also flows through an internal passage to the cavity between the spool and plunger onthe right anti-reaction valve. The pressure goes up through the center of the right spool to thelow pressure side of the swing motor.

The pressure oscillations occur several times while the upper structure stops. The swing anti-reaction opens at the end of each pressure surge to transfer the pressure to the low pressureside of the motors.

By transferring the pressure surges to the low pressure side of the motor the swing operationdecreases to a smooth stop.



109

TRAVEL CIRCUIT

When the travel pedals are actuated for the traveling operation, pilot oil flows through the pilotcontrol valve and pilot lines to the bottom of the travel control valves. The pilot oil pressureshifts the travel control spools up depending upon which direction of travel is desired. Thedecrease in NFC pressure, resulting from the shifted travel control spools, causes the pumps toUPSTROKE. When the travel control spools are shifted up, the pilot logic network passages todrain are blocked. Pilot oil flowing through the left pilot logic network orifice closes the implement/swing pressure switch. The electronic control module (ECM) actuates the automaticengine speed control (AEC) to increase engine speed and start upstroking the pump to meetflow demand.

Oil from the left pump flows through the parallel feeder passage of the left travel control valveand right pump flow is sent through the right parallel feeder passage of the right travel controlvalve. The oil then flows from the travel control valves to the swivel in the center of themachine. From the swivel the oil flows through the counterbalance valves to actuate the travelmotors.

Return oil from the travel motors returns through the swivel and the travel control valve back totank.

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Travel Motor

The two-speed, axial piston travel motors on the 345D are similar in operation to the travelmotors on the 345C. The speed change occurs by changing the angle of the swashplate in thetravel motors. When the swashplate is at maximum angle, the travel motor rotates at slowspeed because the increased displacement of the motor requires more pump flow per revolutionof the travel motor. When the swashplate is at minimum angle, the travel motors rotate at highspeed because the decreased displacement of the motor requires less flow per revolution of thetravel motor.

In addition to the two-speed feature of the travel motors, the system contains the speed changevalve, the travel motor park brake, and the travel motor brake valve.

For high speed travel, the speed change valve receives a pilot signal pressure from the two-speed solenoid on the pilot manifold. The signal shifts the speed change valve which thendirects a system pressure signal to the travel motor swashplate servo piston. The servo pistonshifts the swashplate to minimum angle.

The travel motor park brake is a multiple disc, oil cooled brake that is spring applied andhydraulically released. Travel system pressure is used to release the park brake.

Major components of the travel motor are:

- Supply lines (1)

- Case drain line (2)

- Travel motor brake valve (3)

- Travel motor (4)

110


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34

This visual shows the travel motor and the travel motor brake valve for the 345D with thecomponents listed as follows:

The travel motor counterbalance valve (1) is located in the travel brake valve housing.

When the travel circuits are shifted to HIGH SPEED, the two-speed solenoid on the pilotmanifold sends a pilot pressure signal through the signal hose (2). This pressure signal is usedto shift the speed change valve to the HIGH SPEED position.

The case drain hose (3) is the larger of the two located on the top of the travel motor.

The travel crossover line relief valves (4) are located in the travel brake valve housing.

High pressure hoses (5) connect the hydraulic control valves and the travel motor through theswivel. When the machine is traveling, one of the hoses is the high pressure line and the otherhose is the return to the tank.

111


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This illustration shows the following components of the 345D travel motor:

- Swashplate

- Barrel

- Park brake

- Minimum angle servo piston

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113

Travel Motor Brake Release Valve

The travel motor brake release valve is located in the travel brake valve next to the travel motorbrake valve spool. The brake release valve directs travel pressure to and from the travel parkbrake to release the brake. Spring force applies the travel park brake. The brake release valveslows the application of the travel park brake. By delaying the application of the park brake,the travel motor is stopped hydraulically before the brake is engaged.

System pressure from the reverse travel circuit enters the brake release valve at the center of thevalve. The pressure is also directed to the left end of the brake release valve spool.

As travel system pressure increases, the brake release valve spool shifts to the right. Systempressure flows through the brake release valve to the brake release piston. System pressuremoves the brake release piston up releasing the brake. The relief valve in the brake release portlimits maximum pressure to the brake release piston.


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The two-speed, axial piston travel motors operation is similar to the former machines. Thetravel motors have minimum angle pistons and no maximum angle pistons. The pivot point onthe swashplate is off center. The system pressure on the motor pistons shifts the swashplate tominimum angle.

The travel motor park brake is a multiple disc, oil cooled brake that is spring applied andhydraulically released. Travel system pressure is used to release the park brake.

During travel on level ground, pump oil shifts the counterbalance valve in one direction(depending on which direction the machine is moving). The counterbalance valve then sendssome of the oil to release the park brake. When travel is stopped, the orifice on the end of thecounterbalance valve slows the movement of the counterbalance valve as the valve returns tothe NEUTRAL position to provide a smoother stop.


114

Counterbalance Valve Operation (Level Travel)

When pump supply oil flows into the travel counterbalance valve, part of the oil flows to thedamper chamber which shifts the counterbalance valve spool to the left. At the same time,pump supply oil opens the check valve on the right side of the counterbalance valve spoolwhich allows pump supply oil to flow through the supply port to the rotary group of the travelmotor. A portion of the oil flows through an orifice in the spring chamber of the reversecrossover relief valve. The oil then flows from the spring chamber of the crossover relief valveto the left end of the damper piston and shifts the damper piston to the right against the force ofthe spring. The damper piston absorbs the initial shock of pressurized oil being delivered to thetravel motor system.

As the travel counterbalance valve spool shifts to the left, the throttling slots on the left end ofthe spool open a passage which allows return oil from the rotary group of the travel motor toreturn to the hydraulic tank.

When the oil flow to the travel counterbalance valve is blocked, the pressure oil in the damperchamber on the right end decreases. The force of the centering springs shift the counterbalancevalve spool to the right, and as the spool shifts, the throttling slots on the left side close. Returnoil from the travel motor is blocked and the rotation of the travel motor is stopped.


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115

Counterbalance Valve Operation (Slope Travel)

When the machine travels down a slope, the travel motor rotates at a higher speed. The higherspeed is due to mass (weight and size) of the machine. When this condition occurs, the pumpscannot maintain the oil supply to the travel motors. The lack of oil will cause cavitation in thetravel motors. A pressure decrease occurs at the supply port of the travel counterbalance valveand also occurs in the damper chamber on the right end of the spool as well. The force of thecentering springs moves the spool to the right, and the throttling slots begin to close. As thethrottling slots close, the return oil from the rotary group of the travel motor is restricted. Therestriction of oil from the travel motor causes the rotation of the travel motors to slow down.

As the pressure of the pump oil increases at the supply port to the travel counterbalance valve,the pressurized oil forces the spool to shift to the left which opens the throttling slots on the leftend the spool allowing return oil to flow to the hydraulic tank. The modulation of the spoolmaintains the proper opening of the throttling slots when the machine travels down a slope.The travel motor rotates in accordance to the amount of pump oil supply, which helps toprevent cavitation in the travel motors.


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When the machine is traveling down a slope, or the machine is suddenly stopped, thecounterbalance valve spool is centered by the centering springs and closes the throttling slots.This causes a hydraulic pressure spike to occur in the travel system. A damper chamber isprovided on both ends of the spool to prevent hydraulic pressure spikes. As the spool shifts tothe right, the oil in the damper chamber is pressurized and the ball is moved to the left. Thepressurized oil in the damper chamber is forced through the orifice into the spring chamber. Byslowing releasing the oil in the damper chamber, the counterbalance valve spool slowly movesto the right, and the throttling slots slowly close. The size of the orifice and the position of theorifice maintains the proper shock damper.


116

Travel Crossover Relief Valves (Machine Stop)

If the travel control levers are returned to the NEUTRAL position during the movement of themachine, the pump supply oil is immediately blocked to the travel motors. Without pumpsupply oil, the counterbalance valve spool moves to the centered position blocking the flow ofreturn oil from the travel motors to the hydraulic tank. The mass of the machine causes thetravel motors to continue to rotate, causing a sudden pressure increase in the return oil passage.

The return oil also flows into the spring chamber of the plunger and acts on the poppet in theforward crossover relief valve. The pressurized oil in the spring chamber also flows through apassage up to the right end of the damper piston starting to move the damper piston to the leftagainst the force of the damper piston springs. When the damper piston has moved to the stopon the left, the pressurized oil in the spring chamber of the forward crossover relief valve opensthe poppet seat. The oil flow through the open poppet seat causes a pressure decrease in thespring chamber. The pressure decrease in the spring chamber allows the high oil pressure tomove the plunger to the right allowing the oil to flow past the plunger and back into the supplypassage of the travel motor.


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The crossover relief valve protects the travel motor by releasing the high pressure oil. Thecrossover relief valves also provide makeup oil from the outlet side of the travel motor to theinlet side of the travel motor. This makeup oil prevents a vacuum condition in the travel motor.

During forward travel of the left travel motor, oil flow opens the reverse crossover relief valvewhen the machine is suddenly stopped. During reverse travel of the left travel motor, oil flowopens the forward crossover relief valve when the machine is suddenly stopped.


117

Low Speed Travel

This illustration shows the travel motor in the LOW SPEED (tortoise) position, maximum angledisplacement. The Engine and Pump Controller de-energizes the two-speed travel solenoid.With the solenoid off, no pilot pressure is directed to the right end of the displacement changevalve in the travel motor. When de-energized, the two-speed travel solenoid opens thedisplacement change valve to drain allowing the servo piston to drain into case drain. Thedesign of the travel motors allows the travel system pressure pushing on the pistons in themotor group to move the swashplate to maximum angle when the servo piston is open to drain.

System pressure from the travel control valves goes through the counterbalance valve to thetravel motor. Flow from the circuit with higher pressure (forward or reverse) goes through theball resolver to the end of the displacement change valve where the pressure is blocked.


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118

High Speed Travel

The above schematic shows the travel motor in the HIGH SPEED (rabbit) position. The Engineand Pump Controller energizes the two-speed travel solenoid when the high speed button ispushed in the cab. A pilot signal from the two-speed solenoid shifts the displacement changevalve to the left for HIGH SPEED travel. The travel control valve directs system pressure tothe travel motor. The travel system pressure signal is also directed around the right end of thedisplacement change valve to the servo piston in the travel motor. Travel pressure shifts theservo piston, and the swashplate moves to minimum angle for minimum displacement andHIGH SPEED operation.

When the swashplate is at minimum angle, the travel motor rotates at high speed because thedecreased displacement of the motor requires less flow per revolution of the travel motor.

If the travel system pressure is below approximately 33,000 kPa (4800 psi), the motor will shiftinto high speed. If travel system pressure is above 33,000 kPa (4800 psi), the ECM will notactivate the two-speed travel solenoid. When travelling in high speed and system pressureincreases above the threshold pressure, the ECM automatically shifts the motor to low speed.


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119

Final Drive

The final drive reduces the rotational speed of the travel motor. The output shaft of the travelmotor is splined to the sun gear by a coupling.

The final drive consists of two groups. The first group consists of three stages of the planetarygear reduction. The planetary gear reduction is a series of the planetary gears, the planetarycarriers, the ring gears, and the sun gear. The planetary gear set reduces the travel speedsignificantly through the triple reduction planetary gear sets.

The output group consists of the drive sprocket housing, the ring gear for second and thirdstage, and the cover. With the ring gear and the drive sprocket housing bolted together, thedrive sprocket housing rotates. This causes the track to move in the selected direction.

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120

RETURN HYDRAULIC CIRCUIT

Case drain for the swing and the travel motors return through the motor case drain filter andback to tank.

Case drain for the fan and hydraulic pumps return through the pump case drain filter and backto tank.

Return oil from the main control valve returns back through the slow return check valve, thereturn oil cooler and the return oil cooler bypass back to tank. The slow return check valvemaintains a 400 kPa (60 psi) back pressure in the hydraulic system at all times. This is toprevent the oil in the main control valve from leaking back to tank and leaving an empty voidin the control valve that the pumps have to fill. If the pumps had to fill this void before it sentsystem pressure out to the implements it would cause a jerking motion. The slow return checkvalve helps to prevent this jerking motion.

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WORK TOOLS

The 345D has an extensive selection of work tools to optimize machine production. Choiceinclude hammers, shears, pulverizers, compactors, multi processors, sorting grapples andcouplers as well as several bucket options.

- General Purpose Bucket (GP) - Generally used for digging in low-impact, moderatelyabrasive materials, for example dirt, loam, gravel, or clay.

- Heavy Duty Bucket (HD) - Designed for a wide range of moderately abrasiveapplications such as mixed dirt, clay, and rock. HD buckets have optimized loading anddumping characteristics and more robust construction than the GP buckets.

- Heavy Duty Power Bucket (HDP) - Designed for use in moderately abrasive applicationswhere breakout force and cycle times are critical. Decreased tip radius maximizes tipforce and improves cycle times in most materials. Not ideal for use in sticky materialconditions. Cutting edge and GET are up-sized.

- Heavy Duty Rock Bucket (HDR) - Designed for aggressive bucket loading in highlyabrasive applications such as shot rock and granite. Thick wear plates are utilized toextend the life of the bucket in severe applications.

- Rock Ripping Bucket (RR) - Ruggedly constructed, narrow buckets for ripping inapplications where material penetration and an inability to blast is an issue. Theaggressive lip type ripping design uses five sharp or twin sharp teeth in a staggeredposition. The staggered design allows one or two tips to penetrate first, providing higherbreakout forces.

121


All buckets feature Caterpillar K Series ground engaging tools. The K Series is easier toremove and install due to the vertical retainer utilized by the system. There are a variety ofteeth, side cutters and sidebar protectors available to accommodate operating conditions. Teethare designed to be extremely aggressive and offer excellent penetration. The side cutter designimproved efficiency and bucket payload in trenching applications.


CONCLUSION

This presentation has discussed the component locations and machine systems operation for the345D Hydraulic Excavator.

When used in conjunction with the service manual, the information in this package shouldpermit the technician to do a thorough job of analyzing a problem in these systems.

Always refer to the service manual for the latest service information and specifications whenservicing, testing and adjusting, or making repairs.

122


123

HYDRAULIC SCHEMATIC COLOR CODES

The colors on the hydraulic schematics and cross-sectional views shown throughout thispresentation denote specific meanings. This illustration identifies the meaning of each color.


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SERV1855 - 146 - Laboratory Exercises04/08

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VISUAL LIST

SERV1855 - 147 - Visual List04/08

1. Model View2. Model View3. Compartment Behind Cab4. Pattern Change Valve5. Pattern Change Valve Decal6. Radiator Compartment7. Counterweight Removal System8. Right Side of Machine9. Pump Compartment

10. Hydraulic Pumps11. Left Side of Machine12. Operator Cab13. Seat14. Travel Control Pedals15. Joystick Controls16. Left Joystick17. Right Joystick18. Monitor Panel19. Monitor Panel Close-up20. Monitor Control Buttons21. Hydraulic Activation Lever22. Ground Level Shut-off23. Operator Controls24. Soft Switches25. Rocker Switches26. Backup Switches27. Engine28. Fuel Priming Switch29. Fuel Filters30. Fuel Sensors31. Left Side of Engine32. Right Side of Engine33. Engine Oil Level Sender34. Coolant Flow Switch35. Front Crankshaft Speed Sensor36. Hydraulic System Block Diagram37. Hydraulic System Standby38. Power Shift Pressure System39. Hydraulic Pumps40. Pump Schematic Inputs41. Pump Control Schematic - Standby42. Pump Controls43. Pump Controls - End View44. Pump Controls - Components

45. Pump Controls - Standby46. Pump Controls - Flow Increase47. Pump Controls - Begin Destroke48. Pump Controls - End of Destroke49. Pilot Hydraulic System50. Pilot Pump51. Pilot Filter52. Pilot Relief Valve53. Pilot Manifold54. Hydraulic Activation Lever55. Hyd. Activation Solenoid - Locked56. Hyd. Activation Solenoid - Unlocked57. Swing Park Brake Solenoid58. Two Speed Travel Solenoid59. Pilot Accumulator60. Pilot Logic Network61. Straight Travel Mode62. Pilot Control Valve63. Fan System Block Diagram64. Fan Pump65. Fan Drive System - Maximum Speed66. Fan Drive System - Minimum Speed67. Fan Pump Controls - Maximum Speed68. Fan Pump Controls - Minimum Speed69. Hydraulic Fan Motor70. Main Control Valve - Block Diagram71. Main Control Valve - Components72. Main Control Valve - Neutral73. Pressure Switches74. Main Relief Valve75. Main Relief Valve - Two Stage76. Line Relief Valve77. Bucket Circuit - Bucket Close78. Bucket Circuit - Bucket Open79. Boom Circuit - Boom Up80. Boom Circuit - Boom Lower81. Boom Circuit - Regeneration82. Boom Drift Reduction Valve - Hold83. Boom Drift Reduction Valve - Lower84. Lowering Control Valve - Boom Up85. Lowering Control Valve - Boom Lower86. Boom Priority Schematic87. Boom Priority PRV88. Boom and Swing Priority PRV

VISUAL LIST (continued)

SERV1855 - 148 - Visual List04/08

89. Stick Circuit - Stick Out90. Stick Circuit - Stick In91. Stick Control Valve - Hold92. Stick Control Valve - Stick Out93. Stick Regeneration94. Stick Circuit - Unloading95. Stick Drift Reduction Valve - Hold96. Stick Drift Reduction Valve - Stick In97. Swing Motors98. Swing Circuit - Swing Left99. Swing Circuit PRV without Priority100. Swing Priority PRV - Not 101. Swing PRV102. Swing Circuit - Swing Right Priority103. Swing Motor104. Swing Park Brake - Released105. Swing Crossover Relief Valve106. Swing Circuit Anti-Reaction Valves107. Anti-Reaction Valves - Swing

108. Anti-Reaction Valves - Stop109. Travel Circuit110. Travel Motor111. Travel Motor Brake Valve112. Travel Motor Components113. Travel Motor Circuit - Brake Released114. Counterbalance Valve Operation (Level

Travel)115. Counterbalance Valve Operation (Slope

Travel)116. Travel Crossover Relief Valves (Machine

Stop)117. Travel Motor - Low Speed118. Travel Motor - High Speed119. Travel Final Drive120. Return Hydraulic System121. Model View122. Model View123. Hydraulic Schematic Color Codes

SERV1855 - 149 - Laboratory Exercises04/08 Handout No. 1

Lab A WorksheetsLocate and Identify Pilot System Components

Directions: Place the correct letter or number next to the component. During the visualpresentation, use these worksheets to take notes as the function of each component is explained.

Example: _____Pilot Pump

Location: The single section gear pump mounted on the left main implement pump. Function: Supplies pilot system oil flow to the pilot filter, pilot manifold, and pilot systems.

_____ Pilot Filter

Location:

Function:

_____ Pilot System Pressure Test Port

Location:

Function:

_____ Pilot Manifold

Location:

Function:

_____ Pilot System Pressure Relief Valve

Location:

Function:

_____ Pilot System Accumulator

Location:

Function:


Lab A Worksheets (continued)Locate and Identify Pilot System Components

_____ Swing Parking Brake Solenoid Valve

Location:

Function:

_____ Hydraulic Actuation Control Valve

Location:

Function:

_____ Hydraulic Actuation Solenoid Valve

Location:

Function:

_____ Hydraulic Actuation Lever

Location:

Function:

_____ Power Shift Solenoid Valve

Location:

Function:

_____ Pilot Pressure Release Line for Swing Parking Brakes

Location:

Function:


Lab A Worksheets (continued)Locate and Identify Pilot System Components

_____ Two Speed Travel Solenoid Valve

Location:

Function:

_____ Swing/Boom Priority Valve

Location:

Function:

_____ Implement/Swing Pressure Switches

Location:

Function:

_____ Travel Pressure Switch

Location:

Function:

_____ Pilot System S•O•S Port

Location:

Function:


Lab B WorksheetTest and Adjust Pilot System Relief Valve

Machine Model____________________________ Date__________________________________

Serial Number_____________________________ Service Meter Hours_____________________

Tooling for Pilot Relief Valve Test

____ 1-8T0856 Gauge [6000 kPa (870 psi)]

NOTE: For the complete procedure to test and adjust the pilot system relief valve, refer tothe Service Manual module "345D Excavator Hydraulic System, Testing and Adjusting"(Form RENR7325-03).

Item Specification Actual

Pilot relief valve ____________________ ____________________

NOTE: Test the pilot relief valve pressure with the engine speed dial at Position 10.Hydraulic oil temperature should be 55° ± 5° C (131° ± 9° F°).


Lab C WorksheetLocate and Identify Implement/Travel Pumps and Pump Components

Directions: Refer to the Handout illustration. Place the correct letter next to the component.During the visual presentation, use these worksheets to take notes as the function of eachcomponent is explained.


Location: The single section gear pump mounted on the left pump. Function: Supplies pilot system oil flow to the pilot filter, pilot manifold, and pilot systems.

_____ Implement/Travel Pump Group

Location:Function:

_____ Right Pump

Location: Function:

_____ Left Pump

Location: Function:

_____ Suction Line

Location:

Function:

_____ Discharge Lines

Location:

Function:

_____ Implement/Travel Pumps Case Drain Line

Location:

Function:


Lab C Worksheet (continued)Locate and Identify Implement/Travel Pumps and Pump Components

NOTE: Use the rear pump regulator to identify the following components.

_____ Maximum Angle Adjustment

Location:

Function:

_____ Minimum Angle Adjustment

Location:

Function:

_____ Engine and Pump Control Module

Location:

Function:

_____ Implement/Travel Pump Regulator

Location:

Function:

_____ Power Shift Signal Pressure Port

Location:

Function:

_____ Horsepower Control Pressure Adjustment

Location:

Function:


Lab D WorksheetsLocate and Identify the Main Control Valve and Main Control Valve

Components



Location: The single section gear pump mounted on the left pump.

Function: Supplies pilot system oil flow to the pilot filter, pilot manifold, and pilot systems.

_____ Implement Control Valve

Location:

Function:

_____ Boom I Spool

Location:

Function:

_____ Boom II Spool

Location:

Function:

_____ Bucket Spool

Location:

Function:

_____ Attachment Spool (std.)

Location:

Function:

_____ Straight Travel Spool

Location:

Function:


Lab D Worksheets (continued)Locate and Identify the Main Control Valve and Main Control Valve

Components

_____ Stick I Spool

Location:

Function: _____ Stick II Spool

Location:

Function:

_____ Left Travel Spool

Location:

Function:

_____ Right Travel Spool

Location:

Function:

_____ Line Relief Valves for Boom, Stick, and Bucket Curl

Location:

Function:

_____ Load Check Valves

Location:

Function:

_____ Boom Regeneration Valve

Location:

Function:


Lab D Worksheets (continued)Locate and Identify the Main Control Valve and Main Control Valve

Components

_____ Boom Drift Reduction Valve

Location:

Function:

_____ Stick Drift Reduction Valve

Location:

Function:

_____ Stick Regeneration Valve

Location:

Function:

_____ Swing Control valve

Location:

Function:


Lab E-1 WorksheetTest and Adjust Implement Line Relief Valves


Serial Number____________________________ Service Meter Hours_____________________

Line Relief Valve Pressure Tooling:

____ 1-8T0861 Gauge [6000 kPa (870 psi)] ____ 1-8T0856 Gauge [60000 kPa (8700 psi)]

NOTE: For the complete procedure to test and adjust the line relief valves, refer to theService Manual module "345D Excavator Hydraulic System, Testing and Adjusting" (FormRENR7325-03).

Function Specification Actual

Boom raise ____________________ ____________________

Boom lower ____________________ ____________________

Stick in ____________________ ____________________

Stick out ____________________ ____________________

Bucket open ____________________ ____________________

Bucket close ____________________ ____________________

Attachment, front line relief ____________________ ____________________

Attachment, rear line relief ____________________ ____________________

NOTE: Test the line relief valve pressures with the engine speed dial in Position 2.Hydraulic oil temperature should be 55° ± 5° C (131° ± 9° F°).


Lab E-2 WorksheetTest and Adjust Main Relief Valve


Serial Number_____________________________ Service Meter Hours_____________________


____ 1-8T0861 Gauge [60000 kPa (8700 psi)]

NOTE: For the complete procedure to test and adjust the signal relief valves, refer to theService Manual module "345D Excavator Hydraulic System, Testing and Adjusting"(Form RENR7325-03).


Main relief valve ____________________ ____________________

NOTE: Test the signal relief valve pressures with the engine speed dial at Position 10.Hydraulic oil temperature should be 55° ± 5° C (131° ± 9° F°).


Lab F WorksheetsLocate and Identify Cylinders, Travel System, Final Drive, and Swivel

Components





Location:

Function:


Location:

Function:

_____ Travel Counterbalance Valves

Location:

Function:

_____ Travel Motors

Location:

Function:

_____ Forward Travel Crossover Relief Valves

Location:

Function:

_____ Reverse Travel Crossover Relief Valves

Location:

Function:


Lab F Worksheets (continued)Locate and Identify Travel System, Final Drive, and Swivel Components

_____ Bucket Cylinder

Location:

Function:

_____ Travel Parking Brake

Location:

Function:

_____ Travel Motor Case Drain Line

Location:

Function:

_____ Travel Alarm Cancel Switch

Location:

Function:

_____ Forward Supply Lines

Location:

Function:

_____ Forward Return Line

Location:

Function:


Location:

Function:

_____ Travel Alarm (if equipped)

Location:

Function:


Lab F Worksheets (continued)Locate and Identify Travel System, Final Drive and Swivel Components


Location:

Function:

_____ Two Speed Travel Switch

Location:

Function:

_____ Travel Pedals/Levers

Location:

Function:

_____ Straight Travel Pedal

Location:

Function:

_____ Boom Cylinders

Location:

Function:

_____ Straight Travel Control Valve Spool

Location:

Function:

Lab F Worksheets (continued)Locate and Identify Travel System, Final Drive, and Swivel Components

_____ Swivel

Location:

Function:

_____ Final Drives

Location:

Function:

_____ Stick Cylinder

Location:

Function:


Lab G-1 WorksheetTest and Adjust Travel Crossover Relief Valves

Machine Model____________________________ Date_______________________________

Serial Number_____________________________ Service Meter Hours__________________

Travel Crossover Relief Valve Test Tooling:

____ 1-8T0861 Gauge [60000 kPa (8700 psi)] ____ 1-8T0856 Gauge [6000 kPa (870 psi)]____ 1-FT2542 Track Block Assembly

NOTE: For the complete procedure to test and adjust the travel crossover relief valves,refer to the Service Manual module "345D Excavator Hydraulic System, Testing andAdjusting" (Form RENR7325-03).


Right Forward Travel ____________________ _________________

Right Reverse Travel ____________________ _________________

Left Forward Travel ____________________ _________________

Left Reverse Travel ____________________ _________________

NOTE: Test each travel crossover relief valve pressure with the engine speed dial atPosition 10. Hydraulic oil temperature should be 55° ± 5° C (131° ± 9° F°).


Lab G-2 WorksheetMeasure Travel Motor Case Drain Flow

Machine Model____________________________ Date______________________________

Serial Number_____________________________ Service Meter Hours_________________

Travel Motor Case Drain Flow Tooling:

____ 1-FT2542 Track Block Assembly____ 1-6V9511 Face Seal Plug____ 1-6V9746 O-ring seal____ 1- Hose assembly to fit travel motor case drain fitting____ 1- Stop watch____ 1- Container for Measuring

NOTE: For the complete procedure to test and the travel motor case drain flow, referto the Service Manual module "345D Excavator Hydraulic System, Testing andAdjusting" (Form RENR7325-03).


Right Travel Motor ____________________ ________________

Left Travel Motor ____________________ ________________


Lab H WorksheetsLocate and Identify Swing System Components




Function: Supplies pilot system oil flow to the pilot filter, pilot manifold and pilot systems.

_____ Swing Control Valve

Location:

Function:

_____ Fine Swing Solenoid (Cushion Swing Solenoid)

Location:

Function:

_____ Swing Parking Brake Release Line

Location:

Function:


Location:

Function:


Lab H Worksheets (continued)Locate and Identify Swing System Components

_____ Swing Joystick

Location:

Function:


Location:

Function:

_____ Anti-reaction Valves

Location:

Function:

_____ Swing System Pressure Crossover Relief Valves

Location:

Function:

_____ Variable Swing Priority Valve

Location:

Function:


Lab I-1 WorksheetTest and Adjust Swing System Relief Valves



Swing System Relief Valve Test Tooling:

____ 1-8T0861 Gauge [60000 kPa (8700 psi)]

NOTE: For the complete procedure to test and adjust the swing system relief valves,refer to the Service Manual module "345D Excavator Hydraulic System, Testing andAdjusting" (Form RENR7325-03).


Right Swing MotorRight Swing Relief Valve ____________________ ________________

Right Swing MotorLeft Swing Relief Valve ____________________ ________________

Left Swing MotorRight Swing Relief Valve ____________________ ________________

Left Swing MotorLeft Swing Relief Valve ____________________ ________________



Lab I-2 Worksheet

Test Swing Motor Case Drain Flow



Swing Motor Case Drain Flow Tooling:

____ 1-6V9832 Cap____ 1-6V9746 O-ring seal____ 1- Container for Measuring____ 1- Stop watch

NOTE: For the complete procedure to test and the swing motor case drain flow, referto the Service Manual module "345D Excavator Hydraulic System, Testing andAdjusting" (Form RENR7325-03).


Right Swing Motor ____________________ ________________

Left Swing Motor ____________________ ________________

NOTE: Test the swing motor case drain flow at three different motor positions and thenaverage the three flows. Machine controls are: Engine Speed Dial at Position 10. TheSwing Relief Pressures set at 31400 ± 1000 kPa (4555 ± 145 psi). Hydraulic oiltemperature should be 55° ± 5° C (131° ± 9° F°).


Lab J WorksheetLocate and Identify Cooling and Return Systems Components




Function: Supplies pilot system oil flow to the pilot filter, pilot manifold and pilot systems.

_____ Hydraulic Oil Cooler

Location:

Function:

_____ Radiator

Location:

Function:

_____ Fuel Cooler

Location:

Function:

_____ Air to Air Aftercooler

Location:

Function:

____ Case Drain Filter

Location:

Function:

_____ Return Oil Filter

Location:

Function:


Lab K Worksheet

Test and Adjust Power Shift Pressure

Machine Model____________________________ Date_______________________________

Serial Number_____________________________ Service Meter Hours__________________

Test and adjust power shift pressure test tooling:

____ 2-6V3079 Hose (14 ft. long w/1/8 in. NPTF ext. thd.)____ 4-6V4143 Coupler, Valved (w/1/8 in. NPTF int. thd.)____ 1-8T0856 Gauge [6000 kPa (870 psi)]____ 1-6V3989 Nipple, Open (w/1/4 in. NPTF int. thd.)

NOTE: For the complete procedure to test and adjust the power shift pressure, refer tothe Service Manual module "345D Excavator Hydraulic System, Testing and Adjusting"(Form RENR7325-03).


Low PS Pressure ____________________ ________________

High PS Pressure ____________________ ________________

NOTE: Test and adjust the power shift pressure with the engine speed dial at Position10. Hydraulic oil temperature should be 55° ± 5° C (131° ± 9° F°).


345D Hydraulic EXCAVATORHYDRAULIC SYSTEMS OPERATION POSTTEST

Directions: Modified True/False. If a question is false, underline or circle the word or wordsthat make the statement incorrect and replace with word(s) to make the statement correct.

a hydraulic systemExample: F 1. This is an engine class.

_____ 1. When investigating a power complaint, first determine if the complaint is hydraulicor engine related.

_____ 2. When the implement or travel controls are in use, the implement or travel pressureis regulated by the NFC relief valve.

_____ 3 The engine and pump control module receives an electrical signal from the leftpump pressure sensor during the swing function.

_____ 4. The travel system pressure can be checked while stalling an implement function.

_____ 5. When power shift pressure to the implement pump regulators increases, the pumpsdestroke.

_____ 6. The variable swing priority valve is controlled by the swing priority pressure reducing valve.

_____ 7. Boom pilot pressure controls the swing priority pressure reducing valve.

_____ 8. The Stick 2 stick in pilot signal is controlled by the boom down pilot signal going tothe boom priority pressure reducing valve.

_____ 9. The NFC relief valve system ensures the implement pumps upstroke or destrokedepending on pilot control valve movement.

_____10. The maximum pressure during level travel is regulated by the travel crossover reliefvalve.

_____11. Power shift signal pressure is controlled by the monitor.

_____12. Implement pump G-port pressure oil comes from the pilot manifold.

_____13. The implement pumps upstroke when the power shift solenoid receives a decrease inelectrical signal from the engine and pump control module.

SERV1855 - 172 - Posttest04/08 Handout No. 24

_____14. The Underspeed System regulates NFC pressure to the implement pumps to keepthe engine from stalling.

_____15. The horsepower adjustment on the implement pump regulator controls the pumpdestroking pressure.

_____16. The Boom 1 and Boom 2 control valves move at the same time when Boom Upfunction is activated.

_____17. It is possible to have the stick re-generation not function during a stick in operation.

_____18. When the implement pumps are at standby, the NFC signal pressure is lowest.

_____19. The stick unloading valve is shifted during stick in operation by the stick in pilotpressure.

_____20. The implement pump flow is controlled by three different signal pressures sent tothe pump regulators.

_____21. On all 345Cs, one of the signal pressures that control pump flow is the negativeflow control pressure.

_____22. It is possible to have the boom re-generation not function during a boom down operation.

_____23. When multiple controls are activated, the highest system pressure from the right orleft half of the implement control valve is regulated by the main relief valve.

_____24. Power shift pressure is calibrated using the Service Tool and ET software.

_____25. Diagnostic information is available from the monitor panel or by using ET.


Directions: Fill In The Blank and Multiple Choice. Any reference material and class notesmay be used to determine the correct answers.

1. The travel crossover relief valves are adjusted to what pressure? _____________________

2. What constant power shift pressure is set during P-Q testing? _____________________

3. The boom head end and stick rod end line relief valves are adjusted to what pressure? _____________________

4. The remaining implement line relief valves are adjusted to what pressure? _____________________

5. The engine and pump control does not receive a control signal from .

A. the left and right travel pressure switches B. the implement and swing pressure switch C. the pilot system pressure sensor D. the right pump pressure sensor E. the left pump pressure sensor F.the straight travel pressure switch G. the attachment pressure switch H. the hydraulic activation switch

6. The main relief valve is adjusted to what pressure for implement functions? _____________________

7. The swing motor left and right relief valve pressure setting is adjusted to what pressure? _____________________

8. The travel motor crossover relief valve pressure setting is adjusted to what pressure? _____________________

9. The pilot system pressure is adjusted to what pressure? _____________________

10. The power shift pressure is adjusted to what pressures during the calibration procedure? __________________________________________

11. The travel and swing parking brakes require what pressure to release? _____________________

12. The stick unloading valve requires what rod end return pressure to shift? _____________________



Pilot Pump

Power Shift Pressure Solenoid

Boom and Swing PriorityPressure Reducing Valves

Implement/Swing PressureSwitch

Boom Drift Reduction Valve

Swing Anti-reaction Valves

Hydraulic Actuation Valve

Slow Return Check Valve

Swing Brake Solenoid Valve

Hydraulic Actuation LeverSwitch

Travel Pressure Switches

Negative Flow Control Signals

Straight Travel Valve

Engine and Pump Control

Underspeed System

Stick Unloading Valve

A. Below implement control valve opposite pilotmanifold

B. Control signals from the left and right sectionsof the implement control valve

C. Receives signals from pressure switches andsensors. Sends a PWM signal to the powershift solenoid.

D. Inside spool in left half of implement controlvalve. When activated, sends right pump flowto both travel motors and left pump flow to theimplement and swing functions.

E. Mounted on the right implement pump

F. Destrokes pumps based on engine speed

G. On the front of the swing motor

H. If this switch is closed, the EPC energizes theHydraulic Actuation Solenoid Valve.

I. On top of the right implement pump

J. Prevents the boom cylinders from driftingdown under

K. On pilot manifold. Receives EPC signal andsends pilot system oil to release swing brake.

L. Below the cab on the Travel Control Valve.Signals the EPC when L or R travel is actuated.

M. Controlled by the Hydraulic ActivationSolenoid on the pilot manifold

N. Below the cab on resolver block

O. Provides 290 kPa (42 psi) back pressure in theswing control valve return oil lines.

P. After Stick In return pressure exceeds 15700kPa (2300 psi) this valve shifts openinganother return oil passage for Stick In returnoil.

Directions: Match the component with the correct location or description by placing the letternext to the component.


Lab A Worksheets - AnswersLocate and Identify Pilot System Components

INSTRUCTOR NOTE: Fill in the appropriate letters or numbers as you attach tags tothe components.




_____ Pilot Filter

Location: On the rear of the hydraulic tank at the front of the pump compartment. Function: Filters pilot oil before pilot oil goes to any of the pilot systems.

_____ Pilot System Pressure Test Port

Location: Quick disconnect nipple located on the base of the pilot oil filter. Function: For measuring the pilot system pressure.

_____ Pilot Manifold

Location: Behind the swing bearing, under the main control valve. Function: A manifold block containing the two-speed travel solenoid, hydraulic activation

solenoid, swing brake solenoid, and hydraulic activation control valve. Distributespilot system oil to various systems on the machine.

_____ Pilot System Pressure Relief Valve

Location: On the base of the pilot oil filter. Function: Limits the pilot system pressure.

_____ Pilot System Accumulator

Location: On the top of the pilot manifold. Function: Provides stored energy to the pilot system, when the engine is shut down, for

lowering the implements and dampens pressure spikes in the pilot system duringnormal operation.


Lab A Worksheets - Answers (continued)Locate and Identify Pilot System Components


Location: In the middle of the pilot oil manifold. Function: When energized by the Machine Electronic Control Module, the solenoid sends pilot

system oil to release the swing brakes.

_____ Hydraulic Actuation Control Valve

Location: In the pilot manifold. Function: When actuated by the Hydraulic Actuation Solenoid Valve, this control valve directs

pilot system oil to the pilot joystick.

_____ Hydraulic Actuation Solenoid Valve

Location: On the top of the pilot manifold. Function: When actuated by the Machine Electronic Control Module, this solenoid valve

directs pilot system oil to actuate the Hydraulic Actuation Control Valve.

_____ Hydraulic Actuation Lever

Location: On the left operator console. Function: Opens and closes the hydraulic actuation micro switch. When the hydraulic

actuation micro switch is closed, an electronic signal is sent to the MachineElectronic Control Module. The Machine Electronic Control Module then energizesthe Hydraulic Actuation Solenoid Valve which in turn actuates the HydraulicActuation Control Valve.

_____ Power Shift Solenoid Valve

Location: The front of the main implement pump. Function: It receives an electrical signal from the Machine Electronic Control Module, based

upon engine speed and engine speed dial position, and sends modulated pilot systempressure to the implement pump controls to assist in regulating implement pumpflow.

_____ Pilot Pressure Release Line for Swing Parking Brakes

Location: The pilot pressure line going to the swing brake on the swing motor. Function: Provides pilot system oil from the swing brake solenoid for releasing the swing

brake. The swing brakes are spring applied and released by pilot pressure.


Lab A Worksheets - Answers (continued)Locate and Identify Pilot System Components


Location: The bottom solenoid valve mounted on the pilot manifold. Function: When this solenoid valve is actuated by the Machine Electronic Control Module,

pilot system pressure is sent to the displacement change valves in the travel motors.When the displacement change valves are actuated, the travel motor swashplates areset at the minimum angle for fast travel speed.

_____ Swing/Boom Priority Valve

Location: Under the main control valve, behind the swing bearing.Function: Allows the operator to adjust hydraulic flow priority to the swing or boom circuits,

depending on the movement of the joysticks.

_____ Implement/Swing Pressure Switch

Location: On the front of the main control valve.Function: Signals the Engine and Pump control Module that a implement function is activated

_____ Travel Pressure Switch

Location: On the front of the main control valve..Function: Signals the Engine and Pump control Module that a travel function is activated

_____ Pilot System S-O-S Fitting

Location: On the top left side of the pilot filter base, as viewed from outside the pumpcompartment.

Function: Allows the technicians to obtain S•O•S samples from the hydraulic system.


Lab B Worksheet Answers Test and Adjust Pilot System Relief Valve

Machine Model___________________________ Date_____________________________

Serial Number________________________ Service Meter Hours__________________

Tooling for Pilot Relief Valve Test

____ 1-8T0856 Gauge [6000 kPa (870 psi)]

NOTE: For the complete procedures to test and adjust the pilot system relief valve,refer to the Service Manual module "345D Excavator Hydraulic System, Testing andAdjusting" (Form RENR7325-03).


Pilot relief valve ______________ _________________

NOTE: Test the pilot relief valve pressure with the engine speed dial at Position10. Hydraulic oil temperature should be 55° ± 5° C (131° ± 9° F°).


Lab C Worksheet AnswersLocate and Identify Implement/Travel Pumps and Pump Components

INSTRUCTOR NOTE: Fill in the appropriate letters or numbers as you attach thetags to the components.

Directions: Place the correct letter next to the component. During the visual presentation, usethese worksheets to take notes as the function of each component is explained.



_____ Implement/Travel Pump Group

Location: In pump compartment on center of flywheel housing/pump drive. Function: Supplies oil to the main control valve.

_____ Right Pump

Location: The pump closest to rear of the machine. Function: Supplies oil to the right side of the main control valve.

_____ Left Pump

Location: The pump closest to the front of the machine. Function: Supplies oil to the left side of the main control valve.

_____ Suction Line

Location: The single line connected to bottom center of the implement/travel pump. Function: The supply line from the hydraulic tank to the implement/travel tandem pump.

_____ Discharge Lines

Location: Top of right, left, and pilot pumps. Function: Pump discharge pressure line from each pump to the main control valve.

_____ Implement/Travel Pump Case Drain Line

Location: Connected to top of the right pump.Function: A line sending internal leakage oil from the front pump back to the hydraulic tank.


Lab C Worksheet Answers (continued)Locate and Identify Implement/Travel Pumps and Pump Components

NOTE: Use the rear pump regulator to identify the following components.

_____ Maximum Angle Adjustment

Location: On the rear of the main implement pump directly behind the minimum angleadjustment.

Function: Changes the pump swashplate maximum angle stop to set maximum pump flow.

_____ Minimum Angle Adjustment

Location: On the front of the main implement pump to the right of the power shift solenoid.Function: Changes the pump swashplate minimum angle stop to set minimum pump flow.


Location: The ECM in the compartment behind the cab. Function: Controls the travel proportional solenoids, the travel alarm, the two-speed travel

solenoid valve, and monitors the implement/travel system pressure sensor.

_____ Implement/Travel Pump Regulator

Location: Mounted on the top of each pump. Function: Regulates pump output oil flow based on the signal pressures it receives.

Power Shift Signal Pressure Port

Location: On the back side of the power shift solenoid. Function: Receives the power shift pressure signal from the power shift proportional reducing

solenoid valve.

_____ Horsepower Control Pressure Adjustment

Location: On front of each pump regulator. Function: Regulates the pump discharge pressure point on the constant horsepower curve

where the pump regulator begins to destroke the pump.


Lab D Worksheets Answers Locate and Identify the Main Control Valve and Main Control Valve

Components





_____ Implement Control Valve

Location: Between the swing frame rails in front of the engine. Function: Controls the boom, stick, bucket, travel and attachment functions and contains the

differential relief valves, signal relief valves, and signal duplicating valves.

_____ Boom I Spool

Location: The second spool from the outside in the right half of the implement control valve. Function: Controls the boom function.

_____ Boom II Spool

Location: The first spool from the outside in the left half of the implement control valve. Function: Controls the boom function.

_____ Bucket Spool

Location: The center spool in the right half of the implement control valve. Function: Controls the bucket curl function.

_____ Attachment Spool (Std.)

Location: The fourth spool from the outside in the right half of the implement control valve. Function: Directs oil to an attachment circuit, if the machine is equipped.

_____ Straight Travel Spool

Location: The inside spool on the left main control valve. Function: Directs oil to both travel motors simultaneously.


Lab D Worksheets Answers (continued)Locate and Identify the Main Control Valve and Main Control Valve

Components

_____ Stick I Spool

Location: The second spool from the outside in the left half of the implement control valve. Function: Controls the stick function.

_____ Stick II Spool

Location: The outside spool in the right half of the implement control valve.Function: Controls the stick function.


Location: The second spool from the inside of the left half of the implement control valve. Function: Directs oil to the left travel motor.


Location: The inside spool in the right half of the implement control valve. Function: Directs oil to the right travel motor.

_____ Line Relief Valves for Boom, Stick, and Bucket Curl

Location: The six relief valves are located on the implement control valve. Two are in thebucket curl lines; one is in the boom down line; one is in the boom drift reductionvalve (boom up line); one is in the stick out line; one is in the stick drift reductionvalve (stick in line).

Function: They limit the maximum pressure that can be developed in a circuit due to an outside force on a cylinder.

_____ Load Check Valves

Location: Contained internally within each main control valve. Function: The load check function prevents an implement from moving until pump discharge

pressure is higher than work port pressure.

_____ Boom Regeneration Valve

Location: Is internally plumbed into the valve of the Boom I spool. Function: Directs oil from the head end of the boom cylinders to the rod end of the cylinders

during the Boom lower operation.


Lab D Worksheets Answers (continued)Locate and Identify the Main Control Valve and Main Control Valve

Components

_____ Boom Drift Reduction Valve

Location: On top front of boom I spool on main control valve. Function: Prevents boom cylinders from drifting down due to leakage through the boom spool.

_____ Stick Drift Reduction Valve

Location: On top front of stick I spool on main control valve. Function: Prevents stick cylinder from drifting in due to leakage through the stick spool.

_____ Stick Regeneration Control Valve

Location: Mounted on the rear of the Stick I spool. Function: Directs oil from the rod end of the stick cylinder to the head end during the STICK

IN operation.


Location: The third spool from the inside in the left half of the main control valve. Function: Controls the swing function.


Lab E-1 Worksheet Answers Test and Adjust Implement Line Relief Valves

Machine Model______________________ Date____________________________

Serial Number_______________________ Service Meter Hours_______________


____ 1-8T0861 Gauge____ 1-8T0856 Gauge

NOTE: For the complete procedure to test and adjust the line relief valves, refer to theService Manual module "345D Excavator Hydraulic System, Testing and Adjusting" (Form RENR7325-03).


Boom raise __________________ ________________

Boom lower __________________ ________________

Stick in __________________ ________________

Stick out __________________ ________________

Bucket open __________________ ________________

Bucket close __________________ ________________

Attachment, front line relief __________________ ________________

Attachment, rear line relief __________________ ________________



Lab E-2 Worksheet Answers Test and Adjust Main Relief Valve

Machine Model____________________________ Date___________________________

Serial Number_____________________________ Service Meter Hours______________


____ 1-8T0861 Gauge

NOTE: For the complete procedure to test and adjust the line relief valves, refer to theService Manual module "345D Excavator Hydraulic System, Testing and Adjusting" (Form RENR7325-03).


Main relief valve _________________ ________________



Lab F Worksheets Answers Locate and Identify Cylinders, Travel System, Final Drive, and Swivel

Components


Directions: Place the correct letter or number next to the component. During the visualpresentation, use these worksheets to take notes as the function of each component isexplained.


Location: The single section gear pump mounted on the left pump. Function: Supplies pilot system oil flow to the pilot filter, pilot manifold and pilot systems.


Location: The second spool from the inside of the left half of the implement control valve. Function: Directs oil to the left travel motor.


Location: The inside spool in the right half of the implement control valve. Function: Directs oil to the right travel motor.

_____ Travel Counterbalance Valves

Location: Mounted on the top of the left and right travel motors. Function: Provide passages for pump flow to the left and right travel motors and return flow

from the travel motors to the tank. Also contains line relief valves (crossover reliefvalves) to limit maximum circuit pressure. Internal control spools provide acounterbalance function by applying a partial hydraulic lock on the travel motorsduring stopping and overspeeding conditions.

_____ Travel Motor

Location: Mounted on the inside of the left and right final drive housings. Function: Converts implement/travel pump flow to rotational motion to drive the final drive.

_____ Forward Travel Crossover Relief Valve

Location: Located on the rear top of travel counterbalance valve. Function: Limit the maximum pressure in the travel motor circuits.

_____ Reverse Travel Crossover Relief Valve

Location: Located on the rear bottom of travel counterbalance valve. Function: Limit the maximum pressure in the travel motor circuits to.


Lab F Worksheets Answers (continued)Locate and Identify Cylinders, Travel System, Final Drive, and Swivel

Components

_____ Bucket Cylinder

Location: Mounted on top of the stick between stick and bucket. Function: Opens or closes the bucket.

_____ Travel Parking Brake

Location: Inside the final drive housings. Function: A stack of discs and plates that prevent the final drive from turning unless the

parking brake is released. The travel parking brake is spring applied and releasedwith travel system pressure.

_____ Travel Motor Case Drain Line

Location: On the top of each travel motor. Function: Carries the motor case drain oil (internal leakage oil) back through the swivel to the

tank.

_____ Travel Alarm Cancel Switch

Location: On the right operator console, third button from the top left. Function: When activated, turns the travel alarm off.

_____ Forward Supply Line

Location: Attached to the front of the counterbalance valves. Function: Carry hydraulic oil from the travel control valves to the travel counterbalance

valves.

_____ Forward Return Line

Location: Attached to the front of the counterbalance valves. Function: Carry hydraulic oil from the travel counterbalance valves to the hydraulic return

system.


Location: The ECM in the compartment behind the cab. Function: Controls the travel proportional solenoids, the travel alarm, the two-speed travel

solenoid valve and monitors the implement/travel system pressure sensor.

_____ Travel Alarm

Location: Located below the hydraulic tank. Function: Alerts spectators the machine has begun to move, forward or in reverse.



Components


Location: The bottom solenoid valve mounted on the pilot manifold.Function: When this solenoid valve is actuated by the Engine and Pump Control Module, pilot

system pressure is sent to the displacement change valves in the travel motors.When the displacement change valves are actuated, the travel motor swashplates areset at the minimum angle for fast travel speed.

_____ Two Speed Travel Switch

Location: On the right operator console, top left button. Function: When this key is actuated by the operator, an electrical signal is sent to the Engine

and Pump Control Module. The Engine and Pump Control Module then energizesor de-energizes the two-speed solenoid located on the pilot manifold.

_____ Travel Pedals/Levers

Location: On the cab floor in front of the operators seat. Function: Pushing forward on each pedal/lever sends pilot oil to the travel spool. This moves

the travel control spool which sends hydraulic oil to the travel motor to move themachine in the forward direction. The left pedal/lever controls the left travel motor;the right pedal/lever controls the right travel motor.

_____ Straight Travel Pedal

Location: On the cab floor mounted on the right side of the footrest. Function: Tipping the pedal forward sends pilot oil to the travel spools. This moves the travel

control spools which send hydraulic oil to the travel motors to move the machineforward; tipping the pedal back sends pilot oil to the travel spools. This moves thetravel control spools which send hydraulic oil to the travel motors to move themachine in reverse.

_____ Boom Cylinders

Location: Mounted between the front of the swing frame and the boom arch. Function: Moves the boom up and down.

_____ Straight Travel Control Valve Spool

Location: The inside spool on the left main control valve.Function: Directs oil to both travel motors simultaneously.



Components

_____ Swivel

Location: In the center of the swing frame in front of the swing drives.Function: Provides a rotating joint for implement/travel pump oil, pilot pump oil and travel

motor case drain oil to pass through between the upper and lower structure.

_____ Final Drives

Location: On the rear of the roller frames. Function: Hold the travel motor and travel counterbalance valve assemblies. Reduces the

travel motor rotational speed in three stages.

_____ Stick Cylinder

Location: Mounted on top of the boom between the boom and top end of stick. Function: Moves the stick in and out.


Lab G-1 Worksheet Answers Test and Adjust Travel Crossover Relief Valves

Machine Model__________________________ Date____________________________

Serial Number___________________________ Service Meter Hours_______________

Travel Crossover Relief Valve Test Tooling:

____ 1-8T0861 Gauge [60000 kPa (8700 psi)] ____ 1-8T0856 Gauge [6000 kPa (870 psi)]____ 1-FT2542 Track Block Assembly

NOTE: For the complete procedure to test and adjust the travel crossover relief valves,refer to the Service Manual module "345D Excavator Hydraulic System, Testing andAdjusting" (Form RENR7325-03).


Right Forward Travel __________________ ________________

Right Reverse Travel __________________ ________________

Left Forward Travel __________________ ________________

Left Reverse Travel __________________ ________________



Lab G-2 Worksheet Answers Measure Travel Motor Case Drain Flow

Machine Model____________________________ Date____________________________

Serial Number_____________________________ Service Meter Hours_______________

Travel Motor Case Drain Flow Tooling:

____ 1-FT2542 Track Block Assembly____ 1-6V9509 Face Seal Plug____ 1-6V8398 O-ring Seal____ 1- Hose assembly to fit travel motor case drain fitting____ 1- Stop watch____ 1- Container for Measuring

NOTE: For the complete procedure to test and the travel motor case drain flow, referto the Service Manual module "345D Excavator Hydraulic System, Testing andAdjusting" (Form RENR7325-03).


Right Travel Motor ____________________ _________________

Left Travel Motor ____________________ _________________


Lab H Worksheets Answers Locate and Identify Swing System Components






Location: Third spool from the outside of the left main control valve. Function: Supplies oil to the right and left swing motors when swing function is requested.

_____ Fine Swing Solenoid (Cushion Swing Solenoid)

Location: Mounted on the front of the swing motor. Function: When energized, provides fine control of swing movement by eliminating the abrupt

start and stop during the swing operation.

_____ Swing Parking Brake Release Line

Location: Small line from the swing brake solenoid valve connected to the swing parking brakein the swing drive housing.

Function: Directs pilot system oil from the left swing parking brake to release the swingparking brake in the right swing drive housing.


Location: The second from the bottom solenoid on the pilot manifold. Function: When energized by the Engine and Pump Control Module, the solenoid sends pilot

system oil to release the swing brakes.


Lab H Worksheets Answers (continued)Locate and Identify Swing System Components

_____ Swing Joystick

Location: The left joystick in the cab. Function: Pushing left on the joystick sends pilot oil to the LEFT SWING control valve. This

moves the swing control spool which sends hydraulic oil to the swing motors toswing the machine left; pulling right on the joystick sends pilot oil to the RIGHTSWING control valve. This moves the swing control spool which sends hydraulic oilto the swing motors to swing the machine right.


Location: The ECM in the compartment behind the cab. Function: Controls the swing brake solenoid valve and monitors the swing system pressure.

_____ Anti-reaction Valves

Location: On the bottom front of the swing motor. Function: Help stop the swing smoothly and prevent shock loading at the end of swing

function.

_____ Swing System Pressure Crossover Relief Valves

Location: On the rear of the swing motor. Function: Limit the pressure in the left and right swing circuits during the swing start and stop

operation.

_____ Variable Swing Priority Valve

Location: Mounted under the main control valve, behind the swing bearing. Function: Varies the amount of supply oil that is given to the swing circuit depending on the

movement of the joysticks by the operator.


Lab I-1 Worksheet AnswersTest and Adjust Swing System Relief Valves



Swing System Relief Valve Test Tooling:

____ 1-8T0861 Gauge

NOTE: For the complete procedure to test and adjust the swing system relief valves,refer to the Service Manual module "345D Excavator Hydraulic System, Testing andAdjusting" (Form RENR7325-03).


Right Swing MotorRight Swing Relief Valve ____________________ _________________

Right Swing MotorLeft Swing Relief Valve ____________________ _________________

Left Swing MotorRight Swing Relief Valve ____________________ _________________

Left Swing MotorLeft Swing Relief Valve ____________________ _________________



Lab I-2 Worksheet Answers Test Swing Motor Case Drain Flow



Swing Motor Case Drain Flow Tooling:

____ 1-6V9832 Cap____ 1-6V9746 O-ring Seal____ 1- Container for Measuring____ 1- Stop watch

NOTE: For the complete procedure to test and the swing motor case drain flow, refer tothe Service Manual module "345D Excavator Hydraulic System, Testing and Adjusting"(Form RENR7325-03).


Right Swing Motor ____________________ _________________

Left Swing Motor ____________________ _________________

NOTE: Test the swing motor case drain flow at three different motor positions andthen average the three flows. Machine controls are: Engine Speed Dial at Position10. The Swing Relief Pressures set at 31400 ± 1000 kPa (4555 ± 145 psi). Hydraulicoil temperature should be 55° ± 5° C (131° ± 9° F°).


Lab J Worksheet AnswersLocate and Identify Cooling and Return Systems Components




Location: The single section gear pump mounted on left main implement pump. Function: Supplies pilot system oil flow to the pilot filter, pilot manifold and pilot systems.

_____ Hydraulic Oil Cooler

Location: At the left rear corner of the machine in front of the engine. Function: Provides cooling for the hydraulic oil.

_____ Radiator

Location: At the left rear corner of the machine in front of the engine. Function: Provides cooling for the engine coolant.

_____ Fuel Cooler

Location: At the left rear corner of the machine in front of the engine. Function: Provides cooling for the engine diesel fuel.

_____ Air to Air After-cooler

Location: At the left rear corner of the machine in front of the engine. Function: Provides cooling for the air going into the intake manifold

_____ Case Drain Filter

Location: Inside the pump compartment, behind the pilot filter. Function: Filters the case drain oil from the pumps and motors.

_____ Return Oil Filter

Location: Inside the hydraulic tank. Function: Filter all the return oil from the implements, swing and travel circuits.


Lab K Worksheet AnswersTest and Adjust Power Shift Pressure



Test and adjust power shift pressure test tooling:

____ 1-6V3079 Hose (14 ft. long w/1/8 in. NPTF ext. thd.)____ 2-6V4143 Coupler, Valved (w/1/8 in. NPTF int. thd.)____ 2-8T0856 Gauge [6000 kPa (870 psi)]____ 2-6V3989 Nipple, Open (w/1/4 in. NPTF int. thd.)

NOTE: For the complete procedure to test and adjust the power shift pressure, refer tothe Service Manual module "345D Excavator Hydraulic System, Testing and Adjusting"(Form RENR7325-03).


Low PS Pressure ____________________ _______________

High PS Pressure ____________________ _______________

NOTE: Test and adjust the power shift pressure with the engine speed dial at Position10. Hydraulic oil temperature should be 55° ± 5° C (131° ± 9° F°).

SERV1855 - 199 - Posttest Answers04/08 Handout No. 24

345D Hydraulic EXCAVATORHYDRAULIC SYSTEMS OPERATION POSTTEST

ANSWERS

Directions: Modified True/False. If a question is false, underline or circle the word or wordsthat make the statement incorrect and replace with word(s) to make the statement correct.

a hydraulic systemExample: F 1. This is an engine class.

T 1. When investigating a power complaint, first determine if the complaint is hydraulicor engine related.

main F 2. When the implement or travel controls are in use, the implement or travel pressure is

regulated by the NFC relief valve.

T 3 The engine and pump control module receives an electrical signal from the leftpump pressure sensor during the swing function.

T 4. The travel system pressure can be checked while stalling an implement function.

T 5. When power shift pressure to the implement pump regulators increases, the pumpsdestroke.

T 6. The variable swing priority valve is controlled by the swing priority pressurereducing valve.

swing F 7. Boom pilot pressure controls the swing priority pressure reducing valve.

boom up F 8. The Stick 2 stick in pilot signal is controlled by the boom down pilot signal going to

the boom priority pressure reducing valve.

T 9. The NFC relief valve system ensures the implement pumps upstroke or destrokedepending on pilot control valve movement.

main F 10. The maximum pressure during level travel is regulated by the travel crossover relief

valve.

engine and pump control F 11.Power shift signal pressure is controlled by the monitor.

pump F 12.Implement pump G-port pressure oil comes from the pilot manifold.

T 13.The implement pumps upstroke when the power shift solenoid receives a decrease inelectrical signal from the engine and pump control module.


power shift F 14.The Underspeed System regulates NFC pressure to the implement pumps to keep the

engine from stalling.

T 15. The horsepower adjustments on the implement pump regulator controls the pumpdestroking pressure.

different times F 16. The Boom 1 and Boom 2 control valves move at the same time when Boom Up

function is activated.

T 17. It is possible to have the stick re-generation not function during a stick in operation.

highest F 18.When the implement pumps are at standby, the NFC signal pressure is lowest.

rod end F 19.The stick unloading valve is shifted during stick in operation by the stick in pilot

pressure.

T 20.The implement pump flow is controlled by three different signal pressures sent tothe pump regulators.

T 21.On all 345Cs, one of the signal pressures that control pump flow is the negative flowcontrol pressure.

not possible F 22.It is possible to have the boom re-generation not function during a boom down

operation.

T 23.When multiple controls are activated, the highest system pressure from the right orleft half of the implement control valve is regulated by the main relief valve.

or monitor panel F 24.Power shift pressure can only be calibrated using the Service Tool and ET software.

T 25.Diagnostic information is available from the monitor panel or by using ET.


Directions: Fill In The Blank and Multiple Choice. Any reference material and class notesmay be used to determine the correct answers.

1. The travel crossover relief valves are adjusted to what pressure? 37780 kPa ± 1480 (5480 ± 215 psi)

2. What constant power shift pressure is set during P-Q testing? 2537 kPa (368 psi)

3. The boom head end and stick rod end line relief valves are adjusted to what pressure? 40000 ± 500 kPa (5800 ± 73 psi)

4. The remaining implement line relief valves are adjusted to what pressure? 37000 ± 500 kPa (5076 ± 73 psi)

5. The engine and pump control does not receive a control signal from C .A. the left and right travel pressure switches B. the implement and swing pressure switch C. the pilot system pressure sensor D. the right pump pressure sensor E. the left pump pressure sensor F.the straight travel pressure switch G. the attachment pressure switch H. the hydraulic activation switch

6. The main relief valve is adjusted to what pressure for travel/implement functions? 35000 ± 500 kPa (4950 psi)

7. The swing motor left and right relief valve pressure setting is adjusted to what pressure? 31400 ± 1000 kPa (4554 ± 145 psi)

9. The pilot system pressure is adjusted to what pressure? 4100 ± 200 kPa (595 ± 30 psi)

10. The power shift pressure is adjusted to what pressures during the calibration procedure? 496 kPa (72 psi) 2537 kPa (368 psi)

11. The travel parking brakes require what pressure to release? 1034 kPa (150 psi)

12. The stick unloading valve requires what rod end return pressure to shift? 15700 kPa (2277 psi)


E Pilot Pump

I Power Shift Pressure Solenoid

A Boom and Swing PriorityPressure Reducing Valves

N Implement/Swing PressureSwitch

J Boom Drift Reduction Valve

G Swing Anti-reaction Valves

M Hydraulic Actuation Valve

O Slow Return Check Valve

K Swing Brake Solenoid Valve

H Hydraulic Actuation LeverSwitch

L Travel Pressure Switches

B Negative Flow Control Signals

D Straight Travel Valve

C Engine and Pump Control

F Underspeed System

P Stick Unloading Valve

A. Below implement control valve opposite pilotmanifold

B. Control signals from the left and right sectionsof the implement control valve

C. Receives signals from pressure switches andsensors. Sends a PWM signal to the powershift solenoid.

D. Inside spool in left half of implement controlvalve. When activated, sends right pump flowto both travel motors and left pump flow tothe implement and swing functions.

E. Mounted on the right implement pump

F. Destrokes pumps based on engine speed

G. On the front of the swing motor

H. If this switch is closed, the EPC energizes theHydraulic Actuation Solenoid Valve.

I. On top of the right implement pump

J. Prevents the boom cylinders from driftingdown under load

K. On pilot manifold. Receives EPC signal andsends pilot system oil to release swing brake.

L. Below the cab on the Travel Control Valve.Signals the EPC when L or R travel isactuated.

M. Controlled by the Hydraulic ActivationSolenoid on the pilot manifold

N. Below the cab on resolver block

O. Provides 290 kPa (42 psi) back pressure in thereturn oil lines.

P. After Stick In return pressure exceeds 15700kPa (2300 psi) this valve shifts openinganother return oil passage for Stick In returnoil.

Directions: Match the component with the correct location or description by placing the letternext to the component.

serv1855 (345d) _txt

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