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HYDRAULIC HAMMER

SERVICE MANUAL

GH SERIES HAMMERS GH06 GH3 GH07 GH4 GH1 GH6 GH2/GHS2

7550 Independence Drive Walton Hills, OH 44146-5541

Phone (440) 232-7900 Toll-free (800) 225-4379

Fax (440) 232-6294

© Copyright 2009 NPK Construction Equipment, Inc. www.npkce.com H055-9640A.doc 03/09

“Use Genuine NPK Parts”

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SAFETY Safety notices in NPK Instruction Manuals follow ISO and ANSI standards for safety warnings:

DANGER (red) notices indicate an imminently hazardous situation which, if not avoided, will result in death or serious injury. WARNING (orange) notices indicate a potentially hazardous situation which, if not avoided, could result in death or serious injury. CAUTION (yellow) notices indicate a potentially hazardous situation, which, if not avoided, may result in minor or moderate injury.

ATTENTION (blue) notices in NPK Instruction Manuals are an NPK standard to alert the reader to situations which, if not avoided, could result in equipment damage.

WARNING and BASIC OPERATING INSTRUCTIONS decals are included with each NPK hammer and installation kit. Decals must be installed in the cab, visible to the operator while operating the hammer. STAY CLEAR, PRESSURE VESSEL, GAS PRESSURE and TOOL SHARPENING decals are installed on all NPK hammer models. Keep them clean and visible. NPK will provide decals free of charge as needed.

1. Operator and Service personnel must read and understand the NPK INSTRUCTION

MANUAL to prevent serious or fatal injury. 2. FLYING DEBRIS CAN CAUSE SERIOUS OR FATAL

INJURY. • Keep personnel and bystanders clear of hammer

while in operation. • Do not operate HAMMER without an impact

resistant guard between the HAMMER and operator. NPK recommends LEXAN® or equivalent material, or steel mesh. Some carrier manufacturers offer demolition guards for their machine. Check with the carrier manufacturer for availability. If not available, please call NPK.

3. Do not hardface or sharpen the tool point with a cutting torch. Excessive heat from torching or welding can cause embrittlement, breakage, and flying pieces. Resharpen by milling or grinding only, using sufficient coolant.

ATTENTION

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SAFETY

4. Fully extend the tool while charging the HAMMER with nitrogen gas. Be sure that the retaining pin is installed. STAY CLEAR OF TOOL POINT WHILE CHARGING.

5. Do not disassemble a HAMMER before discharging the hammer gas pre-charge. 6. USE NITROGEN GAS ONLY! Store and handle nitrogen tanks per OSHA

regulations. 7. Avoid high pressure fluids. Escaping fluid under pressure can penetrate the skin

causing serious injury. Relieve pressure before disconnecting hydraulic or other lines.

8. Operate HAMMER from operator’s seat only. 9. Match HAMMER size to carrier according to NPK recommendations, see page 7.

The carrier must be stable during hammer operation and during transport. 10. Do not make any alterations to the TOOL without authorization from NPK

Engineering. 11. Use proper lifting equipment and tools when handling or servicing the HAMMER. 12. Wear ear protection if conditions warrant. Consult OSHA regulations. 13. Wear safety glasses at all times. Beware of flying debris. 14. If modifications are to be made, do not alter the HAMMER without authorization

from NPK Engineering! 15. Use only genuine NPK replacement parts. NPK specifically disclaims any

responsibility for any damage or injury that results from the use of any tool or parts not sold or approved by NPK.

For further safety information, consult the AEM Hydraulic Mounted Breakers Safety Manual, AEM form MB-140 (NPK P/N H050-9600), which is furnished with every NPK hammer. To request an additional copy, please contact NPK at 800-225-4379 or Internet at www.npkce.com.

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CONTENTS SAFETY ..................................................................................................................1 INTRODUCTION.....................................................................................................5 BASIC OPERATING INSTRUCTIONS....................................................................5 PRECAUTIONS FOR USING THE NPK HYDRAULIC HAMMER ..........................6 CARRIER MACHINE COMPATIBILITY ..................................................................7 HAMMER SPECIFICATIONS .................................................................................8 STRUCTURE ..........................................................................................................9 HAMMER SERIAL NUMBER LOCATION...............................................................11 PRINCIPLE OF OPERATION .................................................................................12 HYDRAULIC INSTALLATION .................................................................................13 MOUNTING INSTALLATION ..................................................................................17 ROUTINE INSPECTION AND MAINTENANCE......................................................18 WEEKLY INSPECTION ..........................................................................................19 CHANGING THE TOOL..........................................................................................20 TROUBLESHOOTING ............................................................................................22 CHECKING THE HYDRAULIC PRESSURES ........................................................23 CHECKING THE HYDRAULIC FLOW TO THE HAMMER .....................................24 OIL LEAKAGE.........................................................................................................26 GAS LEAKAGE.......................................................................................................27 EXCESS OIL IN THE GAS HEAD INSPECTION PROCEDURE ............................28 NITROGEN GAS PRESSURE ................................................................................29 GAS CHARGING KIT..............................................................................................29 CHECKING THE GAS PRESSURE........................................................................30 GAS CHARGING THE HAMMER ...........................................................................32 REMOVAL AND MOUNTING OF HYDRAULIC HAMMER .....................................33 TOOLS REQUIRED FOR DISASSEMBLY .............................................................34 NPK START-UP KIT ...............................................................................................35 NPK ASSEMBLY LUBRICANT ...............................................................................36 DISASSEMBLY PROCEDURE ...............................................................................37 DISCHARGING GAS PRESSURE..........................................................................38 DISASSEMBLING THE MAIN BODY......................................................................40 DISASSEMBLY OF MAIN VALVE ..........................................................................46 INSPECTION AND REPAIR AFTER DISASSEMBLY.............................................48 REPAIR SECTION INTRODUCTION......................................................................49 REPAIR TOOLS AND EQUIPMENT.......................................................................49 HAMMER SLEEVE AND PISTON RECONDITIONING TOOLS .............................50 MAIN BODY BORE REPAIR...................................................................................52 PISTON ACTIVE SEAL AREA REPAIR..................................................................62 PISTON TO SLEEVE RUNNING CLEARANCES ...................................................63 REPAIR THE STRIKING END OF PISTON ............................................................64 MAIN BODY SLEEVES...........................................................................................64 REPLACING THE SEALS.......................................................................................65 REASSEMBLY OF THE HAMMER.........................................................................67 STANDARD TOOLS ...............................................................................................83 ACCESSORY TOOLS.............................................................................................83

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CONTENTS MAXIMUM TOOL TO TOOL BUSHING CLEARANCE ...........................................84 NPK HYDRAULIC HAMMER IMPACT BUSHINGS ................................................86 TOOL INSPECTION................................................................................................87 CHISEL TOOL RESHARPENING...........................................................................88 STANDARD LENGTH FOR NPK TOOLS...............................................................89 RETAINING PIN......................................................................................................90 LUBRICATION ........................................................................................................91 AUTOLUBE/UNDERWATER PORT IDENTIFICATION..........................................94 TOOL BUSHING REPLACEMENT .........................................................................95 TOOL HOLDER BUSHING BORE REPAIR............................................................98 TOOL HOLDER ......................................................................................................101 REPLACEMENT OF TIE RODS .............................................................................102 MAXIMUM ELONGATION OF TIE RODS...............................................................104 TORQUE CHART....................................................................................................105 TORQUE VALUES FOR HAMMER FASTENERS..................................................106 MOUNTING PLATE ................................................................................................107 WARRANTY REGISTRATION FOR NEW UNITS ..................................................108 WARRANTY STATEMENT .....................................................................................109 STORAGE OF HYDRAULIC HAMMER ..................................................................110 DECIMAL CONVERSION CHART..........................................................................111 REBUILD SPECIFICATIONS CHECK SHEETS .....................................................112 NOTES....................................................................................................................119 SERVICE RECORD................................................................................................119

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INTRODUCTION

NPK is a leading manufacturer of boom mounted HYDRAULIC HAMMERS, and has the most complete product line available anywhere. The success of NPK is due to our commitment to quality, dependability and long life. The HYDRAULIC HAMMER has many unique designed features and it is a company philosophy that the NPK HYDRAULIC HAMMER can be brought to "like new” condition long after competitive products are scrapped. You can feel confident that you have purchased the best value available.

This comprehensive instruction manual contains instructions for repairing and maintaining NPK HYDRAULIC HAMMERS. This manual includes helpful information for obtaining the full potential and efficiency from NPK HYDRAULIC HAMMERS. Please read this manual thoroughly to understand the NPK HAMMER and its operating principles before using it.

For additional information or help with any problem encountered, please contact your NPK authorized dealer.

Whenever repair or replacement of component parts is required, only NPK parts should be used. NPK is not responsible for failures resulting from substitution of parts not sold or approved by NPK.

BASIC OPERATING INSTRUCTIONS

• READ OPERATORS MANUAL Do not pry with tool. Apply down force perpendicular to work surface. Avoid blank hammering. Do not hammer continuously in the same position for more than 30 seconds.

• Important: It is imperative that grease is maintained in the tool bushing contact area at all times. This may require hourly greasing depending on job conditions. Important: The hammer must be in a vertical position with downforce applied to push the tool all the way in. This prevents grease from entering piston impact area. USE A GOOD QUALITY, HIGH TEMPERATURE EP#2 GREASE CONTAINING ANTIWEAR ADDITIVES. If machine is equipped with an AUTOLUBE System, check grease reservoir daily.

• PERFORM VISUAL INSPECTIONS DAILY Do not operate with loose or missing fasteners, tie rods, etc.

• MAINTAIN A CLEAN HYDRAULIC SYSTEM Keep hoses clean and capped when dismounting or storing hammer. Change oil and filters as recommended by carrier manufacturer.

• DO NOT SUBMERGE HAMMER UNDERWATER Unless modified for underwater operation.

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PRECAUTIONS FOR USING THE NPK HYDRAULIC HAMMER • Perform daily inspections. • Avoid blank hammering. • Do not hammer continuously in the same position for more than 30 seconds. • Do not use the hammer to move material, pry material, or as a pick on material. • Do not use the hammer underwater unless the hammer has been modified for

underwater operation. • Prevent contamination from entering the hydraulic hoses when mounting or

dismounting the hammer from the carrier. • Maintain a clean hydraulic system. Replace the filter element with a new one

and change hydraulic oil at specified intervals. • Operate the hammer carefully. Do not hit the boom of the carrier with the

hammer. • Operate the hammer in a safe manor. Read the NPK Hydraulic Hammer

Operators Manual.

If additional safety information is needed, consult the AEM Hydraulic Mounted Safety Manual. To request a free copy, please contact NPK at 800-225-4379 or e-mail us at www.npkce.com.

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CARRIER MACHINE COMPATIBILITY CHART

These carrier weight ranges are intended as a guideline only. Other factors, such as stick length, counterweights, undercarriage, etc., must be taken into consideration.

Mounting a HAMMER that is too heavy for the carrier machine can be dangerous and damage the machine. Verify carrier stability with hammer before transport or operation.

Mounting a HAMMER that is too small for the carrier machine can damage the HAMMER, cause tool breakage and void Warranties. Please consult NPK Engineering for specific detailed information. CARRIER WEIGHT lbs. (kg)

HAMMER MOUNTING RECOMMENDED RANGE MODEL STYLE lb kg

GH06 Excavator 2,200 - 4,400 1,000 - 2,000

Skid Steer 2,400 - 3,500 1,100 - 1,600

GH07 Excavator 2,800 - 5,500 1,300 - 2,500

Skid Steer 3,000 - 5,500 1,350 - 2,500

GH1 Excavator 5,400 - 9,000 2,450 - 4,100

Skid Steer 5,000 - 7,500 2,300 - 3,400

GH2/GHS2 Excavator 6,600 - 12,000 3,000 - 5,500

Skid Steer 6,000 - 9,000 2,700 - 4,100

GH3 Excavator 8,800 - 15,000 4,000 - 7,000

Skid Steer 8,000 - 14,000 3,600 - 6,400

GH4 Excavator 13,000 - 22,000 6,000 - 10,000

GH6 Excavator 22,000 - 31,000 10,000 - 14,000

*Specifications are subject to change without notice.

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HAMMER SPECIFICATIONS

IMPACT TOOL ENERGY DIA WORKING

HAMMER MODEL

CLASS

FREQUENCY

WORKING WEIGHT

MOUNTINGSTYLE

LENGTH ft lb bpm lbs (Kg) in (mm) in (mm)

GH06 150 480 – 1200 500 (225) Skid Steer 1.7 (42) 12.2 (311) 235 (107) Excavator



GH2/GHS2 500 500 – 1300 800 (365) Skid Steer 2.6 (66) 14.4 (367) 525 (240) Excavator


GH4 1300 400 – 1050 1250 (570) Excavator 3.4 (86) 18.0 (458)GH6 2000 500 – 800 2150 (980) Excavator 4.2 (106) 20.0 (500)

GAS CHARGE PRESSURE 5

OIL FLOW

HYDRAULIC OPERATING PRESSURE 1

CIRCUIT RELIEF

minimum 2 Cold 3 Hot 4

HAMMER MODEL

gpm (L/min) psi (bar) psi (bar) psi (bar) psi (bar) GH06 2.5 – 7 (10 - 25) 1650 (115) 2150 (150) 350 (24) 405 (28) GH07 4 – 9 (15 - 35) 1500 (105) 2000 (140) 350 (24) 405 (28) GH1 7 – 13 (25 - 50) 1750 (120) 2250 (155) 350 (24) 405 (28)

GH2/GHS2 7 – 17 (25 - 65) 2250 (160) 2750 (190) 350 (24) 405 (28) GH3 12 – 26 (45 - 100) 1900 (130) 2400 (165) 350 (24) 405 (28) GH4 13 – 32 (50 - 120) 2200 (150) 2700 (185) 375 (26) 435 (30) GH6 24 – 40 (90 - 150) 2400 (165) 2900 (200) 390 (27) 450 (31)

*Specifications are subject to change without notice.

NOTES: 1. Hydraulic operating pressure maximum is inlet pressure at the hammer with the oil

at operating temperature and with the gas charge set at the hot operating pressure. See CHECKING THE HYDRAULIC PRESSURES section in this manual.

2. Circuit relief pressure is at least 500 psi (35 bar) above hammer operating pressure. 3. Cold gas charge is the initial set with the hammer at ambient temperature. 4. Hot gas charge is checked after 1 to 2 hours of running and with a system oil

temperature of 140° to 180°F (60° to 80°C). This is the preferred check. 5. Pressures listed are maximum. Use tolerance of minus 25 psi (2 bar).

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STRUCTURE

STRUCTURAL DRAWING

MODELS GH06 – GH3

A MAIN BODY B DRAIN PLUG C TOOL HOLDER D RETAINING PIN E RETAINING RING F UPPER TOOL BUSHING (GH3 ONLY) G LOWER TOOL BUSHING J SPACER SECTION L GAS HEAD M CHARGE VALVE N PISTON P MAIN BODY SLEEVE (B) R TOP NUT U WASHER V BOTTOM NUT W VALVE BODY Y VALVE BOTTOM CAP Z VALVE SPOOL

AA PLUNGER BUSHING BB PLUNGER DD SWIVEL ELBOW HH TOOL 30 GREASE FITTING

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STRUCTURE STRUCTURAL DRAWING

MODELS GH4 – GH6

A MAIN BODY B DRAIN PLUG C TOOL HOLDER D RETAINING PIN E RETAINING RING F IMPACT BUSHING w/ UPPER TOOL BUSHING G LOWER TOOL BUSHING J SPACER SECTION L GAS HEAD M CHARGE VALVE N PISTON O MAIN BODY SLEEVE (A) P MAIN BODY SLEEVE (B) R TOP NUT U WASHER V BOTTOM NUT W VALVE BODY Y VALVE BOTTOM CAP Z VALVE SPOOL

AA PLUNGER BUSHING BB PLUNGER DD SWIVEL ELBOW HH TOOL 30 GREASE FITTING

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HAMMER SERIAL NUMBER LOCATION SERIAL NUMBER LOCATION (sn1)

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PRINCIPLE OF OPERATION

OPEN VALVE

(1) UPSTROKE (2) VALVE SHIFT (3) POWER STROKE (4) IMPACT

N PISTON 33 NITROGEN GAS CHAMBER ABOVE PISTON Z MAIN VALVE SPOOL 34 UPPER CHAMBER OF PISTON

BB PLUNGER 35 LOWER CHAMBER OF PISTON HH TOOL 36 CHAMBER OF VALVE SPOOL 5 OUT PORT 37 NITROGEN GAS 6 IN PORT

(1) UPSTROKE OF PISTON Hydraulic oil supplied by the carrier machine hydraulic pump enters the NPK HAMMER

"IN" port (6) and is directed through port (h1) to the top of the valve plunger, forcing the main valve spool (Z) to the down position. Oil flows through the main valve spool (Z) to the lower chamber of the piston (35). The oil pressure acts on the piston (N), raising the piston up, compressing the nitrogen gas (37). Oil in the upper chamber of the piston (34) is forced out the return line through port (h2).

(2) VALVE SHIFT As the piston (N) rises, lower chamber (35) is opened to passage (h3) and oil flows into

the chamber (36) of the main valve spool (Z). Since the area acting on the main valve spool (Z) in chamber (36) is greater than the area of the plunger (BB), the main valve spool (Z) shifts up.

(3) POWER STROKE With the main valve spool (Z) in the up position, chamber (35) is closed off from the "IN"

port (6) and opened to chamber (34) and the return line via passages (h4), (h5), and (h2). The piston (N) is driven downwards by the compressed nitrogen gas (37) as the oil in lower chamber (35) re-circulates to upper chamber (34). When the piston (N) opens passage (h3) to upper chamber (34), the oil in main valve spool chamber (36) is switched to low pressure and the main valve spool (Z) shifts down.

(4) IMPACT The piston (N) impacts the tool (HH) and the main valve spool (Z) shifts to the down

position. High pressure oil is directed to the lower chamber of the piston (35) for the start of another cycle.

AUTOMATIC ENERGY RECYCLING: Extremely hard material will impart greater rebound energy to the piston (N) after it strikes the tool (HH). This will assist the incoming oil in raising the piston (N) against the gas pressure in chamber (33). This reduces upstroke time and therefore increases hammer frequency (beats per minute). The impact force of the hammer remains the same on each impact.

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HYDRAULIC INSTALLATION NPK INSTALLATION KITS are available for virtually all compatible backhoe loaders, excavators, and skid steers. Complete parts and instructions for the hydraulic installation of the NPK HYDRAULIC HAMMER including valving and/or controls, hoses and fittings, boom and stick tubing, and clamps are provided.

HAMMER KIT LINES Typically, the pressure line is arranged on the left side of the boom and the return line on the right side. Flow to the hammer is controlled from an auxiliary valve on the carrier or from an NPK supplied valve. Hydraulic oil, generally, is routed back to the tank thru the excavator’s oil cooler and filter. HAMMER CONTROL VALVE NPK uses two general types of control systems, depending upon the carrier model: 1. CONTROL SYSTEM USING THE CARRIER AUXILIARY OR SPARE VALVE

SECTION. This type of installation utilizes an existing carrier valve. Any additional parts, such as a mechanical linkage, hydraulic pilot actuators, flow control valves, etc. are furnished in the NPK HYDRAULIC INSTALLATION KIT. Special hydraulic pressure control valves are not required. The NPK HYDRAULIC HAMMER operating pressure is self-regulating.

2. CONTROL SYSTEM USING THE NPK MULTIVALVE.

For carriers not equipped with a suitable auxiliary or spare valve section, the NPK HYDRAULIC INSTALLATION KIT includes a solenoid operated, priority flow control valve to operate the NPK HYDRAULIC HAMMER. The NPK MULTIVALVE is specifically designed for the operation of boom mounted attachments.

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HYDRAULIC INSTALLATION PREVENTION OF CONTAMINATION

1. A hydraulic hammer is harder on oil than using a bucket, so the oil is apt to deteriorate and breakdown sooner. Neglect of the oil system can not only damage the hydraulic hammer but also cause problems in the carrier which could result in damaged components. Care should be taken to check for contamination of the oil and to change it if it is found contaminated. Oil sampling at regular intervals is highly recommended.

When the hydraulic oil shows low viscosity and bubbles, this indicates that the oil is

deteriorated. If the oil is dark brown and gives off an offensive odor, it is severely deteriorated. Change the oil immediately!

When the oil is clouded, or the oil filter often becomes clogged, it indicates that the

oil is contaminated. Change the oil immediately!

To change the contaminated hydraulic oil, drain the hydraulic system completely and clean components. Do not mix new oil with the old.

2. Do not allow any contamination to mix with the oil. Take special care in preventing

contamination from entering the hydraulic system through the hose or tube connection when changing the hydraulic hammer with the bucket.

3. Low oil level will cause heat build-up, resulting in deterioration of the oil. Also, it may

cause cavitation due to air mixing with the oil, leading to a damaged hydraulic hammer and carrier components. Keep the oil at the proper level at all times.

4. Do not use the hydraulic hammer at an operating temperature higher than 180°F (80°C). The proper operating oil temperature range is between 120°F (50°C) and

180°F (80°C). Since contaminated cooler fins causes reduced efficiency of the cooler, keep the cooler fins clean at all times. Check the hydraulic oil cooling system to be sure it is working effectively. The use of a heat gun is the best way to evaluate if the cooler is working properly.

5. Water in the hydraulic oil will lead to damage of the hydraulic hammer and carrier.

Drain off water and foreign matter from the hydraulic tank at specified intervals. When out of service, the hydraulic hammer should be stored indoors.

CHANGING THE FILTER ELEMENT AND HYDRAULIC OIL Change the filter element and hydraulic oil at the intervals described in the operation manual of the skid steer or excavator, when using a hydraulic implement. Another method is to set up an oil sampling schedule and change accordingly.

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HYDRAULIC INSTALLATION HYDRAULIC QUICK DISCONNECTS

NPK recommends against the use of non-NPK quick disconnects on hydraulic circuits operating NPK Products. 1. The hydraulic pulsations caused by hydraulic hammer operating can cause internal

pieces of non-NPK quick disconnect (32) to disintegrate. These pieces would migrate into the hammer, causing damage.

2. If quick disconnects are used when the hammer is removed from the excavator, the

quick disconnects should be capped to keep them clean. If this is not done, contamination in the disconnect will be flushed into the hammer when re-connected. This, again, can cause damage.

3. Most quick disconnects create a restriction in the circuit. NPK Hammers are not

back pressure sensitive, but restrictions cause unnecessary heating of the oil. Also, the pressure required to operate the hammer, plus the restriction in the disconnects may push an older, low pressure, carrier machine to the limit of its hydraulic system. This would interfere with proper hammer operation. However, the NPK approved quick disconnects (DX) are properly sized so that the hammer operation is not affected.

NOT RECOMMENDED CONNECTION APPROVED CONNECTION (39) Non-NPK Quick Disconnects (32)

NPK APPROVED CONNECTION QUICK DISCONNECTS CONTACT YOUR NPK DEALER FOR ADDITIONAL INFORMATION ABOUT

NPK QUICK DISCONNECTS (DX)

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HYDRAULIC INSTALLATION HYDRAULIC QUICK DISCONNECTS If hydraulic quick disconnects (32) are used with the NPK Hammer, it is recommended that the following precautions be followed. 1. Periodic inspection of both male and

female ends is recommended to ensure the couplers are in good working condition. Failure to inspect couplers may result in pieces from a damaged or failed coupler to be injected into the hammer or parts of the coupler returned to the machine.

2. Check for dirt, dust, and debris on both

couplers (32) before coupling. 3. Be sure that the couplers are completely

seated together (38). 4. When replacing couplers, be sure that

couplers are replaced as a set, male and female. Do not use one new end and one used end.

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MOUNTING INSTALLATION NPK Mounting Installation Kits include the parts required to adapt the NPK HYDRAULIC HAMMER to the carrier. NPK mounting kits include the hammer mounting bracket, flow control valve (if required), and hoses to connect to the carrier hydraulic system.

m1 Stick Pin (If Required) m2 Link Pin (If Required) m3 (Whip) Pressure Hose m4 (Whip) Return Hose m7 Top Bracket m8 Hammer Bolt Package m9 Klik Pin

*TORQUES OF ALL BOLTS SHOWN ARE WITH THREADS BEING LUBRICATED WITH ANTI-SEIZE COMPOUND.

HAMMER BRACKET ADAPTER BRACKET MODEL BOLT

DIA TORQUE ft/lb (Nm)

BOLT DIA

TORQUE ft/lb (Nm)

GH06 1” 500 (678) 5/8” 165 (225) GH07 1” 500 (678) 5/8” 165 (225) GH1 1” 500 (678) 5/8” 165 (225) GH2/GHS2 1” 500 (678) 5/8” 165 (225) GH3 1-1/4” 1000 (1356) 5/8” 165 (225) GH4 1-1/2” 1250 (1695) 5/8” 165 (225) GH6 1-1/2” 1250 (1695) 1” 550 (745)

*Refer to NPK Installation Kit Manual for additional information.

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ROUTINE INSPECTION AND MAINTENANCE

1. VISUAL INSPECTION Detect a potential problem early.

TIE RODS AND FASTENERS Inspect all fasteners and retighten as necessary. On GH06

through GH4 models, inspect tie rod assemblies for loose top nuts. On the GH6 model, inspect tie rod assemblies for cracked or missing lock plates and lock rings. If these parts are missing, consult NPK Service Department at 800-225-4379. See pages 105 and 106 for torque values.

WELDS Check for cracks, repair as necessary, see page 107. HOSES AND TUBING Check for oil leaks, loose clamps and

hose abrasion. RUBBER MOUNTS Inspect for damage. HYDRAULIC OIL MAINTAIN A CLEAN HYDRAULIC SYSTEM

If non-petroleum oil is used, contact NPK Service Department for compatibility. Keep hoses clean and capped when dismounting or storing hammer. Change oil and filters as recommended by carrier manufacturer. Periodic oil sampling is recommended.

2. DEMOLITION TOOL LUBRICATION Important: It is imperative that grease is maintained in the tool

bushing contact area at all times. This may require hourly greasing depending on job conditions.

Important: The hammer must be in a vertical position with

downforce applied to push the tool all the way in. This prevents grease from entering piston impact area. Pump grease into grease fitting (30) until grease is seen coming out between the tool and bushing.

USE A GOOD QUALITY, HIGH TEMPERATURE EP#2 GREASE CONTAINING ANTI-WEAR ADDITIVES. NPK recommends a Lithium Base, Moly (Molybdenum Disulfide) or other surface protecting additives, EP (Extreme Pressure), NLGI #2 Grease. A high drop point (350° to 400°) grease is desirable.

If machine is equipped with an AUTOLUBE System, check grease reservoir daily.

3. TOOL and TOOL BUSHING WEAR Check the tool and tool bushings for damage, wear or deformation on a regular weekly

basis. Replace the tool and/or bushings when wear exceeds the maximum clearance limit. See MAXIMUM TOOL TO TOOL BUSHING CLEARANCE, see pages 84 and 85.

Do not hardface or sharpen the tool point with a cutting torch. Excessive heat from torching or welding causes embrittlement, breakage, and flying pieces. Resharpen only with a lathe or milling machine using sufficient cooling.

Please consult your authorized NPK Dealer or NPK Service Department for additional information.

• DO NOT SUBMERGE HAMMER UNDERWATER Unless modified for underwater operation.

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WEEKLY INSPECTION 1. TIE RODS AND FASTENERS Inspect tie rod assemblies for cracked or missing lock plates and lock rings. If lock

plates are missing, consult the NPK Service Department at 800-225-4379. Inspect all fasteners and retighten as necessary, see pages 105 and 106.

2. WELDS Check for cracks and repair as necessary, see page 107. Consult your authorized

NPK Dealer or NPK Service Department for additional information. 3. TOOL RETAINING PIN Remove the retaining pin and inspect for peening caused by excessive blank

hammering. If necessary, grind edges smooth as shown in TOOL RETAINING PIN INSPECTION, see page 90. The retaining pin must rotate freely.

4. DEMOLITION TOOL Remove the demolition tool and inspect for peening caused by excessive blank

hammering. If necessary, grind edges smooth as shown in TOOL INSPECTION, see page 87.

5. GAS CHARGE Check and adjust, if required, see pages 29 through 32.

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CHANGING THE TOOL REMOVAL 1. Remove the retaining pin ring (E) by using a screwdriver (t22), see Figures 1 and

2. It will easily come out if pulled at an angle as shown in Figure 2. 2. Screw an M12 bolt (AF) or cap screw into the retaining pin (D), as shown in Figure 3.

1. Pull out retaining pin (D). If the retaining pin (D) is jammed, use a hammer and drift from the opposite side.

Figure 1 Figure 2

Figure 3

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CHANGING THE TOOL

RE-INSTALLATION 1. Clean the retaining pin housing hole and retaining ring groove. 2. Coat the surface of the tool with grease, then install. 3. Apply grease to the retaining ring housing groove. 4. Coat the retaining pin with grease, then install. 5. Install the retaining ring in the following manner:

a. While deforming the retaining ring as shown in Figure 4, partially force it into the groove.

b. Using the handle of the screwdriver, press the rest of the ring into the groove, see Figure 5.

Figure 4 Figure 5

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TROUBLESHOOTING UNDERSTAND THE BASICS:

1. The NPK HYDRAULIC HAMMER hydraulic operating pressure is determined by the nitrogen gas pre-charge pressure in the hammer, not the relief valve setting of the carrier. NPK Hydraulic Hammers are self-regulating for hydraulic pressure.

2. The NPK HYDRAULIC HAMMER energy per blow is determined by the nitrogen gas

pre-charge pressure, not the pump volume. Impact energy is proportional to gas pressure.

3. The NPK HYDRAULIC HAMMER frequency (blows per minute) is determined by oil

flow to the hammer. Frequency is proportional to oil volume (gallons per minute or liters per minute). The hammer circuit must be set to provide the correct flow to the hammer.

TROUBLESHOOTING CHART

PROBLEM CAUSE CHECK REMEDY Loss of impact power. Low gas pressure. Gas pressure Recharge gas. Loss of frequency. (hammer slows down)

Gas pressure too high. Gas pressure Reduce gas pressure.

Shut-off valve partially closed. Valve position Open valve. Relief valve set too low (must be

400 to 500 psi over hammer pressure).

HYD Pressure Adjust or replace.

Hyd. temperature too high (over 180°F).

Oil Temperature Reduce throttle, clean or add oil cooler.

Hydraulic pump volume too low. Oil Flow Increase circuit flow. Oil level of carrier too low. Oil Level Add hydraulic oil. Erratic running or stops running.

Defective pump or control valve. HYD Pressure Repair or replace.

Shut-off valve closed. HYD Pressure Open valve. Hoses reversed. HYD Pressure Pressure is on left. Return is on

right. Return line blocked. HYD Pressure Eliminate obstruction. Oil level of carrier too low. Oil Level Add hydraulic oil. Gas pressure too high. Gas Pressure Reduce gas pressure. Zero gas pressure. Gas Pressure Check for leak and repair. Hammer main valve malfunctioning. HYD Pressure Disassemble and inspect valve

components. Piston not cycling. HYD Pressure Disassemble hammer and

inspect piston.

DETERMINE THE CAUSE OF THE PROBLEM Technical problems are caused by either (1) the hydraulic hammer or (2) the hydraulic system (carrier hydraulics or installation kit). Checking the hydraulic pressure and flow, and the hammer gas pressure, will determine if the problem is in the hammer or the carrier. If the pressures and flow available to the hammer are correct, the problem is in the hammer.

- 23 -

Stay clear of hammer when checking line pressures.

CHECKING THE HYDRAULIC PRESSURES

Install pressure gauges in the hammer pressure and return lines. The NPK INSTALLATION KIT provides pressure test ports in the hammer shut-off valves mounted on the dipper stick. Generally, the pressure line is on the left and the return line is on the right. A glycerin filled gauge should be installed on a hose that is long enough to be clear of the hammer and flying debris.

k1. Stick k3. Check Valve k4. Shut-off Valve k5. On k6. Off k8. Test Ports m3. Pressure Line to Hammer m4. Return Line from Hammer

1. Determine Return Line Pressure

Turn both shut-off valves (k4) to the “on” position and operate the hammer. The return line pressure should not exceed 300 psi (21 bar).

2. Determine System Relief Valve Pressure Turn the pressure line shut-off valve (k4) to the “off” position. Energize the hammer control circuit and note the relief valve setting.

The relief valve is only used for ultimate safety, when the hammer is removed or the shut-off valve is closed, not to set the hammer operating pressure. Therefore, to prevent overheating, loss of flow and reduced hammer frequency, the relief pressure should be set a minimum of 500 psi (35 bar) above the hammer operating pressure.

3. Determine Hammer Operating Pressure Open both shut-off valves. Operate the hammer and note the operating pressure.

The operating pressure of the NPK HYDRAULIC HAMMER is self-regulating, determined by the gas pressure. If the operating pressure is low, check the gas pressure, see pages 29 through 30.

MODEL

HYDRAULIC OPERATING PRESSURE psi (bar)

CIRCUIT RELIEF MINIMUM psi (bar)

GH06 1650 (115) 2150 (150) GH07 1500 (105) 2000 (140) GH1 1750 (120) 2250 (155) GH2/GHS2 2250 (160) 2750 (190) GH3 1900 (130) 2400 (165) GH4 2200 (150) 2700 (185) GH6 2400 (165) 2900 (200)

- 24 -

CHECKING THE HYDRAULIC FLOW AT RATED PRESSURE 1. Installation of a Flow Meter Equipped with Pressure Loading

Valve. Install the flow meter between the hammer pressure line and return as shown below.

Generally, the pressure line is on the left and the return is on the right. 2. Determine Return Line Pressure (Backpressure).

Open both stop valves and press the hammer foot switch. Measure the pressure with the load valve of the pressure / flow meter in full open condition.

- 25 -

CHECKING THE HYDRAULIC FLOW AT RATED PRESSURE

3. Determine Relief Valve Pressure and Oil Flow. Measure flow and pressure with the flow meter. Adjust the load valve to zero restriction. Warm up the hydraulic system of the excavator to normal operating temperature. Set engine throttle to maximum. Press hammer foot switch. Turn in the loading valve knob and record the pressure and flow at regular intervals on graph paper. Record pressure on one axis of the graph and flow on the other. Increase pressure until relief setting is reached. This is the circuit flow chart. Refer to hammer specification chart for correct flow at rated pressure for each hammer.

fm1. Load Valve fm2. Flow/Temperature Display fm3. Flow/Temperature Switch fm4. Pressure Gauge 5. Out 6. In

Typical flow meter with pressure loading valve.

FLOW VS. PRESSURE CHART TYPICAL EXAMPLE

fl FLOW (GPM) pr PRESSURE (PSI)

- 26 -

OIL LEAKAGE Exceeding 180°F (80°C) hydraulic operating temperature reduces seal life. A small amount of oil leakage between the tool and tool bushing at location (pr2) is considered normal. If oil leak is significant, locate the point of origin. Oil running down the tool may be coming from a loose hose. It is normal for a new seal to leak slightly until the seal seats with usage.

POINTS TO CHECK FOR OIL LEAKAGE

PROBLEM CAUSE REMEDY (pr1) Leakage through vent plug. (Small amount is normal)

Seal in main body sleeve A. Disassemble hammer and replace seals.

(pr2) Leakage between tool and bushing. Small leakage is normal here.

Seal in main body sleeve B. Disassemble hammer and replace seals.

(pr3) Leakage between main body and valve.

O-ring between valve and body. Loose bolts.

Replace. Use thread adhesive, tighten.

(pr4) Leakage between valve body and valve top cap.

O-ring under valve cap. Loose bolts.

Replace. Tighten.

(pr5) Leakage between valve body and valve bottom cap.

O-ring under valve cap. Loose bolts.

Replace. Tighten.

(pr6) Leakage between valve and swivel.

O-ring under swivel. Replace.

(pr7) Leakage between hose and swivel.

Loose or damaged hose fitting. Tighten or replace.

(pr8) Leakage between swivel and flange.

Seal in swivel. Replace.

- 27 -

GAS LEAKAGE

(If the gas pressure drops over 25 psi (2 bar) per day). Exceeding 180°F (80°C) hydraulic operating temperature reduces seal life.

TO LOCATE GAS LEAK, APPLY SOAPY WATER (t23) AT THE POINTS INDICATED.

PROBLEM CAUSE REMEDY (pr1) Leakage through vent plug. Seal in main body sleeve A. Disassemble hammer and replace

seals. (pr9) Leakage from top of charge valve.

O-ring in check valve. Damaged check valve in charge valve.

Replace. Replace.

(pr10) Leakage between charge valve and head.

O-ring in charge valve. Loose charge valve.

Replace. Use thread adhesive, tighten.

(pr11) Leakage between head and main body.

O-ring in head. Disassemble hammer and replace seals.

- 28 -

EXCESS OIL IN THE GAS HEAD INSPECTION PROCEDURE As the low pressure oil piston seal in the “A” Sleeve starts to wear out, the piston may pull oil into the gas head. The gas volume is then decreased and the hydraulic oil pressure required to move the piston to its full upstroke position increases. With the hammer suspended, check and adjust the nitrogen gas pressure to the ambient or to the hot specification shown in the chart below. Load the hammer by pressing it against a solid object until the tool stops up inside. The gauge reading should not be much above the loaded gas pressure shown on the chart below. If the loaded gas pressure is high, there is excess oil in the gas head and the hammer must be resealed.

MODEL

PRE-

CHARGE

AT LOAD

PRE-CHARGE

AT LOAD Cold Cold Cold Cold Hot Hot Hot Hot psi bar psi bar psi bar psi bar

GH06 350 24 385 26.5 405 28 450 31 GH07 350 24 385 26.5 405 28 450 31 GH1 350 24 400 27.5 405 28 465 32 GH2/GHS2 350 24 400 27.5 405 28 465 32 GH3 350 24 400 27.5 405 28 465 32 GH4 375 26 425 29.5 435 30 495 34 GH6 390 27 440 30.5 450 31 505 35

NOTES:

1. Cold gas charge is the initial set with the hammer at ambient temperature. 2. Hot gas charge is checked after 1 to 2 hours of running and with a system oil

temperature of 140° to 180°F (60° to 80°C). This is the preferred check.

- 29 -

NITROGEN GAS PRESSURE

The nitrogen gas pressure must be measured with no preload on the tool. Remove the tool; or position the hammer with the tool fully extended against the tool retaining pin. The hammer must not be resting vertical on the tool. The gas pressure in the hammer will vary according to the gas temperature.

PREFERRED METHOD The preferred method to measure or charge the nitrogen gas pressure is with the hydraulic system temperature stabilized after 1 to 2 hours of running and with a system oil temperature of 140° to 180°F (60° to 80°C).

ALTERNATE METHOD The nitrogen gas pressure can be measured or charged at ambient temperature (cold), before operating the hammer. It is recommended the pressure be verified at operating temperature.

DO NOT OVERCHARGE THE HAMMER! Exceeding the gas pre-charge specifications can result in

damaging hammer components. The NPK WARRANTY does not cover failures resulting from exceeding the specified nitrogen gas pressure.

NITROGEN GAS PRE-CHARGE

MODEL

AT AMBIENT TEMPERATURE (cold, before operating)

psi (bar) (plus 0, minus 25)

AT OPERATING TEMPERATURE

psi (bar) (plus 0, minus 25)

GH06 350 (24) 405 (28)

GH07 350 (24) 405 (28)

GH1 350 (24) 405 (28)

GH2/GHS2 350 (24) 405 (28)

GH3 350 (24) 405 (28)

GH4 375 (26) 435 (30)

GH6 390 (27) 450 (31)

GAS CHARGING KIT / PART NO. 7300588

ALL NPK HYDRAULIC HAMMERS are furnished with the following gas charging kit. In addition, a nitrogen tank and pressure regulator valve (not furnished with the hammer) are required. These can be obtained from your local welding supply house. An optional regulator valve is available from NPK.

g1. CHARGE ADAPTER (PART NO. 30604040) g3. PLUG (PART NO. 30102050) g4. HOSE (PART NO. 20118010) g5. CHARGING KIT BOX (PART NO. 35001030) g6. CAP (PART NO. 30100500) g7. OPTIONAL REGULATOR VALVE (PART NO.

21101050)

- 30 -

CHECKING THE GAS PRESSURE

Inspect the nitrogen gas pressure every 100 hours. Note: The gas charge determines the striking power of the hammer. If the gas charge is low, the energy produced by the hammer will be low. PROCEDURE 1. The gas pre-charge is measured with no preload on the tool. Remove the tool or

position the hammer with the tool fully extended. THE HAMMER MUST NOT BE RESTING ON THE POINT.

2. Remove the charge valve cap (M1). 3. Turn the NPK charging adapter T-

handle (g2) full counterclockwise.

4. MODELS GH06, GH07, GH1, GH2/GHS2 Remove plug (g12). Install adapter (g13)

part no. 30604100 into the female port on the gas head. Install NPK charging adapter (g1).

4. MODELS GH3, GH4 and GH6 Only Install the NPK charging adapter (g1)

on the hammer charge valve (M).

Remove the valve cap only, not the charge valve assembly!

5. Tighten the charging adapter cap (g6).

- 31 -

CHECKING THE GAS PRESSURE

6. Turn the T-handle (g2) clockwise. As the T-handle is screwed in, a resistance is

encountered. By turning the T-handle further, the nitrogen gas pressure will be indicated on the pressure gauge (g8). Stop turning the T-handle when the gauge reads pressure. Do not over tighten.

7. Compare the gauge pressure with the NITROGEN GAS PRESSURE CHART, see

page 29. If the gas pressure is 25 psi (2 bar) or more below specification, proceed to NITROGEN GAS CHARGING PROCEDURE. If the pressure is correct, go to the next step.

8. Turn the T-handle (g2) counterclockwise until it stops as in step 3. 9. Slowly loosen the charge adapter cap to relieve the nitrogen gas pressure trapped in

the charge valve. 10. Remove the charge adapter from the hammer charge valve. 11. Remove NPK adapter part no. 30604100. 12. Reinstall existing plug.

- 32 -

GAS CHARGING THE HAMMER PROCEDURE

USE NITROGEN GAS ONLY.

STAY CLEAR OF THE TOOL WHILE CHARGING THE HAMMER WITH GAS. The tool may be impacted by the piston and forced out abruptly.

PROCEDURE 1. Carry out steps 1 thru 4 of CHECKING THE GAS PRESSURE, see page 30.

2. Remove the cap from the charge adapter.

Remove the valve cap only, not the charge valve assembly!

3. Install a pressure

regulator on a tank of nitrogen gas.

4. Connect a hose from the pressure regulator on the nitrogen tank (g9) to the charge adapter (g1).

5. Turn the T-handle (g2) on

the charge adapter (g1) clockwise.

6. Turn the handle (g7) on the tank regulator counterclockwise to fully close.

7. Open the valve (g10) on

the nitrogen tank by turning the T-handle counterclockwise.

8. Slowly adjust the regulator on the nitrogen tank to the correct pressure by turning clockwise. See NITROGEN GAS PRESSURE CHART or decal (g11) on hammer.

9. Charge nitrogen gas until the pressure gauge (g8) on the charge adapter (g1) is at the correct setting, then turn the T-handle (g2) counterclockwise all the way out.

10. Close the nitrogen tank valve and then remove the hose from the charge adapter (g1).

Nitrogen gas may be trapped in the hose. Loosen fittings slowly to release pressure.

11. Remove the charge adapter (g1) from the hammer charge valve.

12. Reinstall existing plug.

- 33 -

REMOVAL AND MOUNTING OF HYDRAULIC HAMMER REMOVAL FROM THE CARRIER

1. Close pressure and return line shut-off

valves (k4). 2. Disconnect hydraulic hoses (AO) before

laying the hammer down. 3. Cap the pressure and return lines on the

carrier and connect the hammer whip hoses.

4. Position the hammer assembly (DR) horizontal on wood blocks (t20) and remove stick pin (m1) and link pin (m2).

The hydraulic lines must be handled carefully and sealed to prevent contamination from entering the hammer or the carrier hydraulic system.

The tool end of the hammer should be set lower than the head end to prevent moisture from entering the hammer through the tool area.

MOUNTING TO THE CARRIER 1. Place the hammer horizontal on wood

blocks (t20), as shown. 2. Align the boom pin holes (m10). Install

the stick pin before the cylinder link pin. 3. Connect hydraulic hoses. PRESSURE is

on left, RETURN is on right. 4. Open shut-off valves.

- 34 -

TOOLS AND EQUIPMENT REQUIRED FOR HAMMER DISASSEMBLY AND ASSEMBLY

NYLON ROD, P/N H010-7510 Used to drive sleeves and piston into and out of main body bore. NPK GAS CHARGING KIT Supplied with the NPK hammer. NITROGEN BOTTLE AND REGULATOR CLEANING SOLVENT NPK ASSEMBLY LUBRICANT SUITABLE NYLON SLING DRAIN PAN LIFTING HOOK, P/N H010-7501 For removing and installing tool holder.

HEX KEY WRENCHES SHCS SIZE

HEX SIZE

NPK PART NO.

M10 8mm 25004080 M12 10mm 25004100 M16 14mm 25004140 M20 17mm 25004170 M24 19mm 25004190 M27 19mm 25004190

LONG HEX KEY SOCKETS When repairing NPK hammers, it is sometimes necessary to remove the socket head cap screws on the main valve. NPK has available 1” drive long sockets (t24) to aid disassembly. Use with a hex key wrench (t25) modified into a straight key by cutting (40) off the short end of the wrench as shown.

HEX SOCKET

SIZE

NPK PART NO.

14mm 35004590 17mm 35004600 19mm 35004610

HOIST The minimum hoist capacity should be determined by the hammer model. Refer to HAMMER SPECIFICATIONS (see contents) for hammer weights. SLUGGING WRENCH (Optional) SOCKET WRENCHES See TORQUE CHART for sizes. SLEDGE HAMMER Size according to hammer model. PLASTIC HAMMER ADJUSTABLE WRENCH PORTA POWER HYDRAULIC PUMP AND CYLINDER With chain accessory attachments, P/N T000-1031

- 35 -

NPK START-UP KIT All new NPK Hammers are shipped with a start-up kit, part number H251-5100. This kit will contain the following:

Gas Charging Kit (Red Box)

Two (2) tubes of NPK grease for start up

Plugs and Caps

Manuals and Warranty Information

- 36 -

NPK ASSEMBLY LUBRICANT NPK ASSEMBLY LUBRICANT is specially formulated to provide quick, positive lubrication. Oil rich ingredients, plus a free-flowing light lithium grease, offer top lubrication, as well as long lasting protection against rust and corrosion. NPK ASSEMBLY LUBRICANT even “creeps” into remote, normally inaccessible areas to lubricate and safeguard interior metal surfaces. NPK ASSEMBLY LUBRICANT is ideal for use on all metal-to-metal surfaces.

DIRECTIONS FOR USE 1. Wipe off exposed surfaces. 2. Shake vigorously to thoroughly mix contents. 3. Spray liberally on areas requiring lubrication. NPK ASSEMBLY LUBRICANT contains NPK-10 Metal Treatment and is ideal for use in the assembly of all NPK products. NPK ASSEMBLY LUBRICANT comes in a 16 ounce bottle with sprayer and can be ordered using part number H010-5010.

- 37 -

DISASSEMBLY PROCEDURE

A sturdy work bench is recommended for disassembly and assembly of an NPK HYDRAULIC HAMMER.

REMOVE THE HAMMER FROM THE BRACKET

1. Place the hammer on blocks (t20). Make sure the hammer is stable.

NOTE: DO NOT REMOVE TOOL FROM HAMMER AT THIS TIME! 2. Remove the bracket bolts (m11), nuts

(m12), and washers (m13). 3. Remove hydraulic hoses. Plug hose ends and

hammer ports to prevent contamination from entering. 4. Lift the hammer (KK) from the bracket (LL). Using a

hoist, attach a chain (t4) or strap (t27) to the hammer and lift it out of the bracket (LL).

- 38 -

DISCHARGING THE GAS PRESSURE

PROCEDURE

1. Remove the charge valve cap (M1). 2. Turn the NPK charging adapter T-handle (g2) counterclockwise until it stops.

3. The NPK GH06, GH07, GH1 and GH2/GHS2 hydraulic hammers have a gas charge fitting in the gas head that is different from all other NPK hydraulic hammers. After removing the existing plug (g12), the adapter (g13), part no. 30604100 is threaded onto the existing GH06, GH07, GH1 and GH2/GHS2 gas charge fitting. This adapter is included in the gas charge kit that is provided with the hammer and allows use of the standard NPK gas charge valve (g1), part no. 30604040.

4. Install the NPK charging adapter (g1) on the hammer charge valve (M).

- 39 -

DISCHARGING THE GAS PRESSURE PROCEDURE

Loosen the charge adapter cap (g6) only, not the charge valve assembly!

5. Tighten the charge adapter cap (g6).

6. Turn the T-handle (g2) clockwise. As the T-handle is screwed in, a resistance is encountered. By turning the T-handle (g2) further, the nitrogen gas pressure will be indicated on the pressure gauge (g8). Stop turning the T-handle when the gauge reads pressure. Do not over tighten.

7. Loosen the charge adapter cap (g6) VERY SLOWLY. The gas pressure will gradually decrease to zero; then REMOVE THE CAP.

8. Remove the charge

adapter (g1) from the hammer.

9. Remove NPK adapter

part no. 30604100. 10. Install existing plug.

- 40 -

DISASSEMBLING THE MAIN BODY

Check to see that the nitrogen gas has been completely discharged.

1. Remove the top nuts. Loosen the pair ‘A’ and ‘D’ or ‘B’ and ‘C’ first. Then,

loosen the remaining pair uniformly until the spacer spring tension is relieved.

2. Remove the nuts. 3. Remove the lockwashers (U).

- 41 -

ATTENTION

DISASSEMBLING THE MAIN BODY 4. Remove the gas head and spacer springs.

a. Pry off the gas head using screwdrivers or pry bars as levers. Care should be exercised so as not to apply undue force. Remove the gas head from the tie rods.

When the gas head is removed, hydraulic oil will flow out of the body bore. Therefore, have oil pans ready.

b. Remove the spring washers (AG).

5. Sling (t27) or hook (t28) the tool holder (C).

The tool holder must be kept level and square to the main body.

- 42 -


Loosen the tie rods (Q) with a wrench (t6) by hand. If a tie rod (Q) should fail to turn, rap the bottom nut (V) with a hammer (t29). If the tie rods (Q) are still tight, re-position the tool holder to remove the bind on the tie rods (Q). Loosen all four of the tie rods (Q) before removing any of them.

6. Pull out the tie rods (Q).

7. Hoist the tool holder by a crane to

remove it from the main body.

8. Remove the spacer section (J).

Hoist the spacer section (J) by a sling (t27) to remove it from the main body.

- 43 -


MODELS GH4 – GH6 9. Remove the dowel pins (K) from the

main body “B” sleeve (P).

10. Remove the piston and “A” and “B” sleeves as one unit. a. Bump a nylon bar (t3) on the end of

the piston at the tool holder end (1) and drive the sleeves (O,P) and piston out.

Hydraulic oil comes out of the body each time the sleeves move. Direct the port of the swivel adapter downward.

b. To prevent damage to the body

bore, support “A” sleeve (O) with a sling (t27) as it comes out.

c. Do not use a steel bar to drive out sleeves!

Use a nylon strap (t27) to support the piston and sleeves as they are removed from the body bore.

- 44 -

DISASSEMBLING THE MAIN BODY d. Alternate method of piston and sleeve removal - pin chain to diagonally opposite

tie rod holes in main body at tool end (1).

String chain through tie rod holes and wrap around back of portable power unit, NPK part no. T000-1031.

e. Push piston and sleeves from the tool end of body and out gas end (2).

MODELS GH06 – GH3 HAVE NO “A” SLEEVE 1. GH06 through GH3 Tap the “B” sleeve (P) and the piston (N) out of the hammer body (A) towards

the tool end (1) using a nylon bar or a dead blow hammer handle (t2) as shown.

- 45 -


MODELS GH4 – GH6

f. Keep the sleeves (O,P) level by adjusting tension on the sling (t27).

When the sleeves come out of the body, hydraulic oil flows out. Have an oil pan ready to catch it.

g. Lay the piston (N), “A” sleeve (O) and “B” sleeve (P) assembly on a piece of cardboard (t30) on a table (t31).

Do not use steel bar to drive apart sleeves!

h. Separate “A” sleeve (O) from the piston (N) by tapping the sleeve with a dead blow hammer (t2).

When removing the sleeves and piston as a unit, the point of balance will be on the “B” sleeve (P) near where the “A” sleeve (O) joins it.

11. Remove the piston (N) from the “B” sleeve (P). Separate the piston (N) from the “B” sleeve (P) by rapping the striking end of the piston (N) with a dead blow hammer (t2). The piston (N) will slide out of the “B” sleeve (P).

ATTENTION

- 46 -

DISASSEMBLY OF MAIN VALVE

1. Remove the bottom cap (Y) from

the main body (W).

a. Remove the cap screws from the bottom cap (Y) with a hex wrench (t25) and extension bar (t32).

b. Remove the bottom cap (Y). Use a screwdriver (t22) (or pry bar) to remove cap (Y).

Do not force the bottom cap (Y) when removing it, otherwise, the valve body (W) will be damaged, causing oil leaks.

2. Remove the plunger bushing (AA).

a. Remove cap screws from the plunger bushing (AA) with a hex wrench.

b. Use a nylon bar (t3) in the main valve body (W) at the bottom cap end (3) and

drive the plunger bushing (AA), and the valve spool (Z) out of the case with a hammer.

- 47 -

DISASSEMBLY OF MAIN VALVE

c. Remove the valve spool (Z) from

the valve body (W). d. Remove the plunger (BB) from the

plunger bushing (AA).

e. Remove the swivel adapters.

1. Remove the snap ring (AJ) with

snap ring pliers, then remove the washer (AH). Pull the swivel elbows (DD) off of the swivel flanges (EE).

2. Remove the cap screws (OO) from the swivel flanges (EE) and then remove the swivel flanges (EE).

f. Remove the main valve body. It is rarely necessary to remove the valve body from the main body. If disassembly is needed for any reason, proceed as follows.

Attach a 6 ft. (2 meter) long

extension pipe to the hex wrench and with it loosen each bolt. There is thread adhesive on each bolt. Use heat on the head of any bolt that is found difficult to remove.

DO NOT HEAT EXCESSIVELY!! DO NOT HEAT THE VALVE

CASE OR MAIN BODY!!

ATTENTION

- 48 -

INSPECTION AND REPAIR AFTER DISASSEMBLY

As a rule, disassembly of the hydraulic hammer is only required when a problem occurs. Periodic disassembly for inspection is not required. 1. Sealing materials - any sealing

material that is found deformed, worn or damaged as shown, must be replaced.

a. Deformed, worn, distorted,

damaged or deteriorated o-ring.

b. Worn or deformed backup ring. c. Worn or deteriorated u-cup seal. 2. Hammer Internals

a. Piston - Check the sliding areas for

damage and the striking area for damage or deformation. Repair or replace, if necessary.

b. “A” and “B” sleeves – Check the inner surface for

damage and repair or replace if necessary. Complete hammer check sheets and fax to NPK for advice on reuse of main components.

3. Tool and Tool Bushing Wear - See pages 84 and 85 of this

manual, “Maximum Tool to Tool Bushing Clearance”.

4. General - a. Check for damage, breakage,

deformation, wear and rust and repair or replace, if necessary.

b. Check for contamination and remove, if any.

c. Valve spool – Check the sliding area for

damage, deformation, or wear and repair or replace, if necessary.

d. Valve case – Check the inner surface for

damage or wear and repair or replace, if necessary.

e. Swivel adapter – Check the seal contact area for

damage or wear and repair or replace, if necessary.

- 49 -

REPAIR SECTION INTRODUCTION

The NPK HYDRAULIC HAMMER is a rugged boom-mounted demolition tool which, by its application, is subjected to severe repeated shock forces. Based on long years of experience, NPK has carefully selected the best materials, heat treatment, and machining to obtain the longest life possible. All critical components are 100% inspected and identified by serial number. However, as with all machines, it is necessary to perform periodic maintenance and repairs. The personal attention and cost required for maintenance will be repaid many times over in trouble-free, low cost operation. The NPK replaceable sleeve concept is an exclusive feature that greatly extends the useful service life of the NPK HYDRAULIC HAMMER. When competitive products without this exclusive feature must be scrapped, the NPK HYDRAULIC HAMMER can be completely rebuilt. This comprehensive SERVICE MANUAL contains detailed instructions for repairing major components to achieve the extended life. Please read this SERVICE MANUAL thoroughly before attempting any major repair of the hammer. For additional information or help with any complex problem encountered, please contact the NPK ENGINEERING DEPARTMENT. Call toll free 1-800-225-4379. Whenever repair or replacement of component parts is required, only parts sold by NPK should be used. NPK is not responsible for failures resulting from substitution of parts not sold or approved by NPK.

REPAIR TOOLS AND EQUIPMENT

Air or electric handheld grinder (NPK brand air grinder is recommended, p/n NHG-65LD). NPK Assembly Lube, p/n H010-5010. Polishing wheel (available from NPK, p/n 25026030). Oil stone Emery cloth (200 grit) Cleaning solvent

- 50 -

HAMMER SLEEVE AND PISTON RECONDITIONING TOOLS When repairing NPK Hammers, it is sometimes necessary to polish the piston, sleeves or main body bore. NPK has available for purchase, a hand held, long shaft straight grinder. NPK also sells the appropriate polishing and groove cleaning wheels to be used in reconditioning these parts. The part numbers are provided below for ordering purposes.

ITEM PART NO. DESCRIPTION t1 NHG-65LD LONG SHAFT STRAIGHT GRINDER

t7

25026050 POLISHING WHEEL – used for cleaning seal grooves in sleeves. (Green)

t8

25026030

POLISHING WHEEL – used for final polishing of piston, sleeves and main body bore. (Gray)

t9 25026020 GRINDING WHEEL – used to grind weld. (Red)

t10

T050-7500

CUT-OFF WHEEL – used to clean and repair pressure balancing grooves in the sleeve land area.

- 51 -

HAMMER SLEEVE AND PISTON RECONDITIONING TOOLS

(t7) 25026050 POLISHING WHEEL (GREEN) USE THIS WHEEL FOR CLEANING OUT SEAL GROOVES IN NPK “A” AND “B” SLEEVES.

(t8) 25026030 FINISH POLISHING WHEEL (GRAY) USE THIS WHEEL FOR FINAL POLISHING OF PISTON, MAIN BODY AND GLAND RING AREA OF NPK “A” AND “B” SLEEVES.

(t9) 25026020 GRINDING STONE (RED) USE THIS STONE FOR GRINDING WELD IN HAMMER MAIN BODY.

(t10) T050-7500 CUT-OFF WHEEL USE CUT-OFF WHEEL TO CLEAN AND REPAIR PRESSURE BALANCING GROOVES IN NPK “A” AND “B” SLEEVES.

NOTE: WHEN RECONDITIONING PARTS, IF YOU ARE UNSURE OF THE

PROPER PROCEDURES, CONSULT THE NPK SERVICE MANUAL OR CONTACT THE NPK SERVICE DEPARTMENT AT 1-800-225-4379.

- 52 -

MAIN BODY BORE REPAIR

INSPECTION AND GENERAL POLISHING OF MAIN BODY After disassembly and cleaning of the hammer components, it is important to carefully inspect the hammer main body bore. 1. Using a light, look into the bore and identify all locations (9) of the o-rings that

seal the sleeve O.D. to the body. These areas can be recognized by the black markings left in the bore from the o-rings resting in these areas.

2. If no damage is noted in the o-ring areas, use a ball hone to break the glaze in

the bore of the body. DO NOT USE A FIXED HONE! USE ONLY 6 STROKES OF A BALL HONE!

REMEMBER: ONCE THE SLEEVES ARE INSTALLED, THE O-RINGS BECOME STATIONARY AND DO NOT MOVE OUT OF THE AREA THEY REST IN. 3. If a scratch runs across several o-ring areas:

a. Polish o-ring rest areas to blend with surrounding area. b. If scratches are not removed by use of a ball hone, see Repairing Body

Bore By Grinding and Polishing. 4. If score in o-ring area is too deep to polish and blend, the body may be welded in

these areas and hand ground / polished, see Repairing Body Bore By Welding and Polishing.

- 53 -

MAIN BODY BORE REPAIR NPK RECONDITIONING TOOL USING THE NPK AIR GRINDER If cavitation erosion is found in the main body, in most instances it can be addressed by light polishing in the area of erosion. DO NOT HONE THE BODY! 1. Take an NPK polishing wheel, part no. 25026030 (gray) (t8) and taper (45) each

side so that the wheel is “V” shaped. This can be done by holding the wheel against the edge of a metal surface for several seconds.

2. Using a rocking motion, polish the erosion groove until the rough edges are

removed. This must be done so that the o-rings on the O.D. of the sleeves will not be damaged during installation.

3. Clean bore using a ball hone making no more than 6 strokes. DO NOT HONE

USING A FIXED HONE! 4. After polishing, clean main body bore to remove all grinding debris. NOTE: WHEN REASSEMBLING THE HAMMER, USE A LIBERAL AMOUNT OF

GREASE IN THE POLISHED AREA.

- 54 -

MAIN BODY BORE REPAIR REPAIR OF BODY BORE BY GRINDING AND POLISHING

(10) POLISHED AREA

IDENTIFY O-RING AREAS (9)

The areas (9) of the bore that are sealed by o-rings can be located by the discoloration. To prevent oil and/or gas leakage, special care must be taken to obtain a smooth finish with no pinholes, undercut, or uneven finish in the o-ring areas. If you are unsure of where the o-ring areas are located, measure these areas on the outside of the sleeves and mark in the body using a permanent marker to show o-ring areas. If a deep score (11) or scratch (deeper than .006 inch (.15 mm), that cannot be repaired by grinding is found in the body bore, repair this by welding, see Repairing Body Bore By Welding and Polishing.

- 55 -

MAIN BODY BORE REPAIR

REPAIR OF BODY BORE BY GRINDING AND POLISHING

GRIND ROUGH EDGES OF THE ENTIRE LENGTH OF THE SCRATCH. (t8) POLISHING WHEEL (GRAY)

POLISH SCRATCHES IN THE O-RING AREAS (9) TO A SMOOTH SURFACE. BLEND THIS AREA TO THE SURROUNDING SURFACE. DO NOT OVER POLISH!

CHECK BORE DIMENSION WITH A BORE GAUGE (t11), COMPARE WITH SPECIFICATIONS SHOWN IN CHART ON PAGE 61.

- 56 -

MAIN BODY BORE REPAIR REPAIR OF BODY BORE BY GRINDING AND POLISHING After polishing, remove all o-rings from the “B” sleeve (longest sleeve). Apply a light coat of NPK Assembly Lubricant, part no. H010-5010. Pass the sleeve in and out through the bore to check for any high spots, which require additional polishing.

9. REPAIRED O-RING – CONTACT SURFACE 12. GROUND AREA – NO O-RINGS HERE

- 57 -

MAIN BODY BORE REPAIR REPAIRING DEEP BODY BORE SCRATCHES BY WELDING AND POLISHING If a deep score or scratch (11) (deeper than .006 inch (.15 mm), that cannot be repaired by grinding is found in the body bore, repair this by welding. The areas of the bore that are sealed by o-rings can be located by the discoloration (9). To prevent oil and/or gas leakage, special care must be taken to obtain a smooth finish with no pinholes, undercut, or uneven finish in the o-ring areas. If you are unsure of where the o-ring areas are located, measure these areas on the outside of the sleeves and mark in the body using a permanent marker to show o-ring areas.

IDENTIFY O-RING AREAS

REPAIR PROCEDURE:

1. Carefully grind the score (11) until it is flush with the surface, especially in the o-ring rest areas, as in area (10).

(10) POLISHED AREA

- 58 -

ATTENTION

MAIN BODY BORE REPAIR REPAIRING DEEP BODY BORE SCRATCHES BY WELDING AND POLISHING 2. Clean and mark the o-ring areas. (weld should extend 1/2” on either side of the o-

ring contact area). Preheat the area(s) to be welded to approximately 300°F (150°C). This will remove oil and insure a better weld. Weld using a small diameter welding rod such as: AWS 6013 or AWS 7018 (or equivalent). Mask the area around the location to be welded. This will prevent “spatter” damage to the remaining bore area.

Use care to prevent an undercut. AFTER WELDING, BEFORE GRINDING AFTER GRINDING AND POLISHING

3. After welding, grind weld until almost flush with the bore. Change to a fine polishing

stone and finish until flush or just below flush. The seal areas of the o-rings cannot tolerate undercut and/or rough surfaces.

DO NOT HONE BODY WITH A FIXED HONE! USE A BALL HONE ONLY MAKING NO MORE THAN 6 PASSES.

4. After polishing area, remove all

o-rings and backup rings from “B” sleeve. Push “B” sleeve through body to check for high spots. If sleeve will not go through body, identify high spots and continue polishing.

- 59 -

MAIN BODY BORE REPAIR REPAIRING DEEP BODY BORE SCRATCHES BY WELDING AND POLISHING 5. Remove all o-rings from the “B” sleeve (longest sleeve). Apply a light coat of NPK

Assembly Lubricant, part no. H010-5010. Pass the sleeve in and out through the bore to check for any high spots, which require additional polishing.

9. REPAIRED O-RING – CONTACT SURFACE 12. GROUND AREA – NO O-RINGS HERE

- 60 -

MAIN BODY BORE REPAIR HONING MAIN BODY Generally, honing of the main body is not recommended. This is due to trying to maintain the I.D. of the body as close to the new standard dimension as possible. However, when honing is required, the use of a ball hone is recommended. Using a fixed power hone is not recommended, (consult NPK before using a fixed power hone). The guidelines for using a ball hone are outlined below: 1. Apply a light coat of NPK Assembly Lubricant, p/n H010-5010 or equivalent oil.

2. Using the proper size hone as shown in the following chart, push / pull the hone

through the body 6 times using even strokes.

3. Clean bore of the body. Check dimensions of I.D. Compare to the chart on page 61. If dimensions are within usable limits, reassemble the hammer. If dimensions are outside the allowable range, contact NPK for assistance.

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MAIN BODY BORE REPAIR MAIN BODY BORE DIMENSIONS

GH SERIES HAMMERS

MODEL

d5 MAIN BODY

BORE – NEW

d6 MAIN BODY

BORE – MAX*

d7 MAIN BODY

LENGTH

BALL HONE SIZE

PART

NUMBER INCH MM INCH MM INCH MM

GH06 2.954 75.04 2.965 75.30 14.97 380.3 N/A N/A 2.953 75.00 14.96 380.0

GH07 2.954 75.04 2.965 75.30 14.97 380.3 N/A N/A 2.953 75.00 14.96 380.0

GH1 3.545 90.04 3.555 90.30 18.12 460.3 4” T050-7600 3.543 90.00 18.11 460.0

GH2/GHS2 3.939 100.04 3.949 100.30 18.52 470.3 4” T050-7600 3.937 100.00 18.50 470.0

GH3 4.529 115.04 4.539 115.30 20.49 520.5 4-1/2” T050-7605 4.528 115.00 20.47 520.0

GH4 4.923 125.04 4.933 125.30 24.82 630.5 6” T050-7610 4.921 125.00 24.80 630.0

GH6 5.907 150.04 5.917 150.30 27.58 700.5 6” T050-7610 5.905 150.00 27.56 700.0

NOTE: *Body bore maximum I.D. is not to exceed .010” (.25 mm) above standard

(new) dimension. If bore is at or above this dimension, call the NPK Service Department at 1-800-225-4379.

- 62 -

PISTON ACTIVE SEAL AREA REPAIR PISTON REPAIR PROCEDURE Pistons with scratches or scoring in the active seal areas, denoted as d10 and d11 in the illustration, may be repaired by polishing as long as the damage is less than .1mm (.004 inch) deep. Damage more than .1mm (.004 inch) deep requires piston replacement. Note that scratches in area d12 are not as critical, but the diameter of area d12 is. After repairing a piston in areas d10, d11, or d12, measure the diameters with a micrometer and contact the NPK Service Department to confirm that the piston is still within usable specifications. Areas d8 and d9 are not critical. Light buffing to smooth out scratches is all that is required.

MODEL

d8

in mm d9

in mm d10

in mm d11

in mm GH06 1.14 29 1.18 30 4.17 106 4.17 106 GH07 1.18 30 1.22 31 4.17 106 4.17 106 GH1 1.61 41 1.73 44 5.20 132 4.65 118 GH2/GHS2 1.61 41 2.05 52 5.20 132 4.65 118 GH3 2.17 55 2.56 65 5.51 140 5.08 129 GH4 2.2 56 2.8 71 7.32 186 5.98 152 GH6 2.56 65 3.31 84 7.80 198 6.38 162

- 63 -

PISTON TO SLEEVE RUNNING CLEARANCES The clearances shown below are to be used in determining if the internal components of the hammer are reusable. Measure the inside diameter of the sleeve and subtract the outside diameter of the piston at each location shown. Note, in the NPK Hydraulic Hammer Service Manual, the drawing of a piston shown in the piston repair section. There are three critical surfaces marked d10, d12, and d11. Each surface has a corresponding “Land” in the “A” or “B” sleeve through which the piston rides. These lands can be recognized by the multiple oil control grooves.

If the measurements are smaller than the values shown in the chart below, the piston and sleeves are reusable. If any of the measurements exceed the values shown, call the NPK Service Department at 800-225-4379, for recommendations on parts replacement.

MODEL d10

in mm d11

in mm d12

in mm GH06 .010 .25 .010 .25 .004 .11 GH07 .010 .25 .010 .25 .004 .11 GH1 .010 .25 .010 .25 .004 .11 GH2/GHS2 .010 .25 .010 .25 .004 .11 GH3 .010 .25 .010 .25 .004 .11 GH4 .010 .25 .010 .25 .004 .11 GH6 .010 .25 .010 .25 .006 .15

- 64 -

REPAIR THE STRIKING END OF PISTON The NPK piston is designed for maximum fatigue resistance to failure of the striking face. The striking face can become indented and mushroomed when the hammer has been used for a long time or operated with worn-out tool bushings. To repair the piston, dress the tool striking end with a grinder.

MODEL

NEW d13 MINIMUM d14

inch mm inch mm GH06 13 329 12.70 323 GH07 13.10 332 12.80 326 GH1 15.60 396 15.30 388 GH2/GHS2 16 406 15.70 398 GH3 17.90 454 17.50 444 GH4 21.40 544 21.00 534 GH6 23.50 598 23.10 588

MAIN BODY SLEEVES

REPAIR OF SLEEVE INSIDE DIAMETER Scoring or galling may occur when the hammer has been used for a long period of time; or operated with worn-out tool bushings, loose tie rods, overheated hydraulic system, or contaminated hydraulic oil. If the sleeve has slight scratches or scoring, then repair by polishing. Call NPK for detailed information. If the sleeve is damaged from scoring or galling in the axial direction, the oil grooves may be filled with metallic particles. The oil grooves must be cleaned or they will cause additional scoring.

- 65 -

REPLACING THE SEALS If the gas pressure drops more than 25 psi (2 bar) a day or a large oil leak is found, replace the seals.

Check the seals, seal grooves, and piston active seal areas for damage. 1. Small nicks may be removed with a suitable hone. 2. When large or deep nicks are found, replace the part.

GH06 – GH3

A. BODY P. “B” SLEEVE PP. U-CUP SEAL QQ. DIRT SEAL RR. O-RING SS. BACKUP RING 1. TOOL END 2. GAS END

NOTE: GHS2 has extra machining for the anti-blank firing feature.

GH4 – GH6

O. “A” SLEEVE P. “B” SLEEVE AP. WEAR BAND PP. U-CUP SEAL QQ. DIRT SEAL RR. O-RING SS. BACKUP RING 1. TOOL END 2. GAS END

(DEFECTIVE SEALS) ALL DEFECTIVE SEALS SHOULD BE REPLACED WITH NEW ONES.

41. O-RINGS DEFORMED, WORN,

WARPED, DAMAGED OR DETERIORATED

42. BACKUP RINGS WORN OR DEFORMED

43. U-CUP SEALS WORN OR DETERIORATED

Some minor leakage may be found for a while after new oil seals are installed, the oil leak will stop when the seal seats itself in use.

- 66 -

ATTENTION

REPLACING THE SEALS

1. INSTALLING THE U-CUP SEALS

a. One method of folding u-cup seals (PP) is illustrated below. Insert flat side into groove.

HOW TO HOLD THE U-CUP SEAL b. Installation should be performed quickly, taking care to observe the correct

direction. Taking too much time might let the u-cup take a set, which could cause leaks.

c. Care should be exercised as not to damage the lip

when installing the u-cup seal. Installation of damaged u-cup seals will cause oil leaks.

d. After installing u-cups in the sleeve, coat them with

grease to assist with piston installation. e. GH06 – GH3 only – install seal (PP) from gas end (2)

of hammer body.

2. INSTALL THE O-RINGS AND BACK UP RINGS

a. Install the o-rings. b. Curl the back up rings, as shown below, and install. c. After installing, coat the o-rings and back up rings with grease.

Inspect sleeves to verify that the o-rings, back up rings, and u-cup seals are correctly arranged.

- 67 -

REASSEMBLY OF THE HAMMER Reassemble the hydraulic hammer in the reverse order of disassembly. 1. Before reassembling, clean all parts carefully. Since the hydraulic hammer is a

precision machine, dust or dirt adversely affects the performance.

2. Reassemble the main body.

a. Place the main body (A) on the

workbench (t31). b. Check the fit of “B” sleeve (P).

Lightly oil the body bore. Before installing the o-rings on the sleeve, slide it through the bore from one end to the other. The sleeve should move smoothly without binding.

3. Install “B” sleeve.

a. Apply hydraulic oil on the seals and install them in “B” sleeve (P).

b. Apply hydraulic oil or NPK

assembly lube to the bore of the main body.

c. Push “B” sleeve (P) into the

main body (A) bore from the gas head end with pressure port (6) and tank port (5) facing upward. Insert the sleeve using a sling (t27) until the seals reach the body bore. Bump the sleeve into the bore until it is almost flush with the end of the body. Use a dead blow hammer (t2) or a nylon bar. Keep the sleeve level as it enters the bore.

NOTE: USE AN OLD LOCK PLATE (S) TO PREVENT THE “B” SLEEVE (P) FROM TRAVELING INTO THE MAIN BODY (A) BORE.

- 68 -

REASSEMBLY OF THE HAMMER MODELS GH4 – GH6

4. Install the piston (N).

a. Apply hydraulic oil or NPK assembly lube to the inner surface of “B” sleeve (P).

b. Insert the piston into “B” sleeve (P) by moving the free end up and down.

Care should be exercised so as not to damage “B” sleeve when moving the piston up and down.

5. Install the dowel pins (K). Apply a small amount of grease on

the two dowel pins and install them in “B” sleeve (P). The grease holds the pins in place.

6. Install “A” sleeve (O).

a. Install the seals in “A” sleeve (O).

b. Apply hydraulic oil on the inner

surface of the sleeve. c. Align the dowel pin holes with

the dowel pins in “B” sleeve (P) and insert “A” sleeve (O).

d. Push “A” sleeve (O) over the

piston until it contacts “B” sleeve (P) and traps the dowels.

Be sure that the “A” and “B” sleeves have no gap between them before pushing them into the main body.

ATTENTION

ATTENTION

- 69 -

REASSEMBLY OF THE HAMMER

ALTERNATE METHOD OF INSTALLING THE PISTON AND SLEEVES INTO THE MAIN BODY

This is the preferred method as it keeps the piston and sleeves together as one unit. This prevents sleeve separation, which could allow dowels to drop out of place. Also, the steady push of the portable power unit reduces the possibility of cutting o-rings or back up rings.

1. Pin chain (t4) to diagonally opposite

tie rod holes (44) in main body (A) at tool end (1).

String chain (t4) through tie rod holes and wrap around back of portable power RAM cylinder (t5).

Support the end of the “B” sleeve (P) with a sling (t27) and insert into the gas end of the main body (A). Bump with a dead blow hammer (t2). Align ports with main body (A).

Push “B” sleeve into body from gas end of body (1) with portable power unit (t33).

Push “B” sleeve (P) using a push plate (t26) almost flush with gas end of body (1). Watch o-rings and back up rings as they enter bore. If seal starts to extrude, stop and push seal back into groove.

- 70 -

REASSEMBLY OF THE HAMMER ALTERNATE METHOD OF INSTALLING THE PISTON AND SLEEVES INTO THE MAIN BODY 2. Install two dowel pins (K) into each end of “B” sleeve (P). Apply a sufficient

amount of grease to prevent the pins from falling out.

3. Using a lock plate as a stop to keep “B”

sleeve (P) from going any further at this point.

4. Install the piston (N). 5. Install “A” sleeve (O).

Carefully insert the piston (N) into “B” sleeve from the gas end of the main body.

Apply lubricating oil or NPK assembly lube to inside and outside diameters of “A” sleeve (O). Align dowel pin holes and install “A” sleeve (O) onto piston (N), flush with “B” sleeve (P).

a. MODELS GH06 - GH3

Tap the “B” sleeve (P) and the piston (N) into the hammer body (A) from the tool end (1) gently tapping using a dead blow hammer (t2) as shown.

- 71 -


6. Use portable power unit (t33) to push “A” sleeve (O), piston, and “B” sleeve into position from the gas end (1). Use the dimensions in the chart on page 72 to locate final position. Take care to watch o-rings and back up rings on the sleeves as they enter the bore.

7. Make sure “B” sleeve is in proper

position. See chart below for installation dimensions of correctly installed sleeves.

A. MAIN BODY O. MAIN BODY “A” SLEEVE P. MAIN BODY “B” SLEEVE 5. OUT PORT 6. IN PORT

- 72 -


Push the piston and sleeves into the body bore until the ports in “B” sleeve (P) line up with the ports in the body. Check dimension (d1) to be sure sleeves are in their correct location. Check d2. If d2 is less than the value shown, then “A” sleeve (O) is not fully engaged into “B” sleeve (P). Hold “B” sleeve (P) and try and bump “A” sleeve (O) into position. If this doesn’t work, the sleeves must be bumped back out of the bore until “A” sleeve (O) comes clear. The problem can then be identified and corrected.

MODELS GH06 – GH3 A. MAIN BODY P. MAIN BODY “B” SLEEVE d1. DIMENSION (END GAP) BOTTOM 1. TOOL END 2. GAS END 5. OUT PORT (TANK) 6. IN PORT (PRESSURE)

MODELS GH4 – GH6 A. MAIN BODY O. MAIN BODY “A” SLEEVE P. MAIN BODY “B” SLEEVE d1. DIMENSION (END GAP) BOTTOM d2. DIMENSION (END GAP) TOP 1. TOOL END 2. GAS END 5. OUT PORT (TANK) 6. IN PORT (PRESSURE)

MODEL

d2 inch mm

d1 inch mm

GH06 N/A N/A .69 18 GH07 N/A N/A .69 18 GH1 N/A N/A .75 19 GH2/GHS2 N/A N/A .78 20 GH3 N/A N/A .94 24 GH4 1.25 31 1.12 29 GH6 1.62 41 1.25 32

- 73 -

REASSEMBLY OF THE HAMMER 8. Apply a thin coat of grease on the o-

ring (RR) and push it into the body bore (7) and up against the end of the “B” sleeve (P).

9. Install the o-ring (RR) into the counter

bores of the grease passage of the spacer section (J). Seal the o-ring (RR) into place with a bead of RTV Silicone.

10. Install the spacer section (J). Align the

dowel pins on the “B” sleeve with dowel pin holes in the spacer section (J). Make sure grease passages are aligned.

11. Make sure the spacer section (J) is

snug to the body. If the spacer section (J) is not square to the body, it is because the sleeves are slightly rotated out of position. Take a dead blow hammer (t2) and rap sharply on the high corner of the spacer section (J). This will rotate the spacer section (J) and sleeves into correct position.

- 74 -

REASSEMBLY OF THE HAMMER 12. Install the tool holder and tie rods.

a. Check the threads in the tool holder.

b. Apply anti-seize compound to the

threads of the tie rods. c. Hoist the tool holder by a crane

(t34), using slings or a hammer hook (t28), and install it onto the spacer section with the retaining pin plug (I) facing upward as shown.

d. Install tie rods (Q) into the body

from gas head end using a hand wrench (t6).

The tool holder must be level and square to the main body. Do not use an air wrench to thread the tie rods into the bottom nuts.

ATTENTION

- 75 -

REASSEMBLY OF THE HAMMER e. Turn each of the tie rods (Q) clockwise

with a hand wrench (t6) until several threads are engaged. Turn each tie rod until it bottoms in the bottom nut (V) then back off tie rods two turns. Support tool holder (C).

13. Install the spring washers (AG). Apply a thin coat of grease (28) on the

spring washers and install them with the gap at edge as shown below.

a. Pour specified amount of synthetic

oil in past “A” sleeve. Any viscosity synthetic motor oil is acceptable.

OIL CAPACITY

MODEL CAPACITY

OUNCE (cc) GH06 1.5 (40) GH07 1.5 (40) GH1 1.75 (50)

GH2/GHS2 3.5 (100) GH3 3.5 (100) GH4 3.5 (100) GH6 5 (150)

NOTE: SPRING WASHERS ARE NOT USED IN GH06 – GH3 HAMMERS.

- 76 -


b. Install the o-ring (RR) on the boss of the gas head. Apply grease on the surface of the o-ring before installing it on the gas head.

Be careful pushing the gas head into position so as not to disturb the spring washers.

14. Install the gas head (L) and lock

washers (U). a. Install the lock washers (U) onto tie

rods (Q).

b. Apply anti-seize compound on the lock washer faces and tie rod threads.

ATTENTION

- 77 -

REASSEMBLY OF THE HAMMER 15. Install the top nuts (R) and tighten by

hand.

a. If a gap (d3) of about .19 - .25 inch

(7 to 8 mm) is formed between the main body (A) and the gas head (L) when the top nuts (R) are tightened fully by hand, the setting may be regarded as normal. If the gap (d3) is larger than the mentioned dimension, this suggests that the spring washers have fallen out of position.

16. Tighten all TOP NUTS with a TORQUE WRENCH to recommended torque

specification shown in CHART 1, see page 105. (It may take several passes at each top nut to achieve this.) Check that no gap (d3) is noted between the sections.

- 78 -

REASSEMBLY OF THE HAMMER 17. Prepare for main valve installation. 17.1 Install the o-rings.

a. Install the o-rings and the back up

rings on the main body. b. Install the o-ring and the back up ring

on the underside of the valve body. c. Apply a thin coat of grease (28) on the

o-rings and the back up rings.

17.2 Fill hammer assembly (KK) with oil.

Pour oil (t52) into the “IN” port (6) and the “OUT” port (5) of the hammer assembly. Let air that is trapped in the assembly purge out.

17.3 Install the valve body (W).

a. Install the valve body (W) on the main body.

b. De-grease the bolts and tapped holes

in the main body. c. Apply adhesive on the bolts and

tighten them to the specified torque, see page 106.

17.4 Install the bottom cap (Y).

a. Apply a thin coat of grease on the

o-ring (RR) and backup ring (SS) and install them on the bottom cap (Y). (Curl the back up ring to form a small circle before installing).

- 79 -

REASSEMBLY OF THE HAMMER b. Insert the bottom cap (Y) into the

valve body (W) by carefully tapping it with a dead blow hammer (t2).

c. Tighten the bolts evenly to the

specified torque, see page 106.

17.5 Install the valve spool (Z). Apply hydraulic oil or NPK

assembly lube to the surface of the valve spool (Z). Then insert the valve spool (Z) from the top side into valve body (W). Make sure that the valve spool (Z) moves smoothly.

17.6 Install the plunger (BB) and the plunger bushing (AA).

a. Apply a thin coat of grease on

the o-rings (RR) and back up rings (SS) and install them on the plunger bushing (AA). (Curl the back up ring (SS) to form a small circle before installing.)

- 80 -

REASSEMBLY OF THE HAMMER b. Apply grease to the surface of the

plunger (BB). Insert grease into the plunger bore of the plunger bushing (AA). Then insert the plunger (BB) into the plunger bushing (AA).

c. Insert the plunger bushing in the valve

body with the plunger operation pilot hole upward (8).

d. Tap carefully with dead blow hammer.

e. Tighten the bolts to the specified torque,

see page 106.

- 81 -

REASSEMBLY OF THE HAMMER 17.7 Install the swivel flange (EE).

a. Apply grease (28) to the o-rings (RR) and the back up rings (SS), then install them on the swivel flange (EE). Install the swivel flange on the valve body.

b. Tighten the bolts to the specified

torque, see page 106.

c. Apply grease to the o-rings and the back up rings. Install them in the swivel elbow (DD). Install the seal rings (AI), the swivel elbow (DD), and stop ring (AH) on the swivel flange.

d. Using snap ring pliers, install the snap

ring (AJ) on the swivel flange (EE).

The JIC fitting on the swivel adapter is off set to clear the swivel flange bolts.

- 82 -

REASSEMBLY OF THE HAMMER 18. Install the tool and retaining pin. 19. Charge with nitrogen gas and inspect

for gas leaks.

a. Charge nitrogen gas to the specified gas pressure. See “Gas Charging the Hammer” pages 29 through 32.

b. Check for gas leaks. See “Gas

Leakage” page 27.

20. Grease the tie rods (GH6 ONLY).

a. After the tie rods have been torqued, install grease fittings (30) as shown. Grease until no more grease is accepted. Remove the grease fittings and install the existing plugs (TT).

21. Install the hammer into the hammer

bracket.

- 83 -

STANDARD TOOLS

DEMOLITION TOOL SHAPE APPLICATIONS

CHISEL (FX) The cross cut (FX) tool cuts at right angle, or crosswise, to the stick and boom of the excavator.

• Trenching • Cutting casting gates • Breaking oversize • General demolition

MOIL (P)

• Concrete breaking • Highway construction • General demolition

BLUNT (E) • Secondary breaking

• Breaking oversize • Slag removal

OPTIONAL TOOL

CORE (PC) for GH6

• Concrete breaking • Highway construction • General demolition

ACCESSORY TOOLS

SPECIALTY TOOL SHAPE APPLICATIONS

FROST CUTTER Cross cut (SX), In Line (SY) for GH07 thru GH4

• Edge of trenching • Frost cutting

ADAPTER TOOL for GH07 thru GH4

• For attachments listed below

TAMPER PLATE (use with adapter tool)

9-1/2” x 9-1/2” for GH07 12” x 12” for GH1 thru GH2/GHS2 16” x 16” for GH3 thru GH4

• Soil compaction • Driving sheeting

POST and PIPE DRIVER (use with adapter tool)

for GH1 thru GH4

• Driving guard rails • Driving fence posts

TOOLS FROM H & E SERIES HAMMERS WILL NOT FIT GH SERIES! ATTENTION

- 84 -

MAXIMUM TOOL TO TOOL BUSHING CLEARANCE Replace the tool bushing upper (F) or lower (G), and/or tool (HH), when the tool to bushing gap reaches the maximum clearance. To determine whether the bushing or tool requires replacement, follow the instructions and charts shown below: Step 1 Measure the tool to bushing gap (d15) with the hammer horizontal, as illustrated below. If the clearance is at or greater than the charted maximum clearance, then move on to the next steps.

MODEL

MAXIMUM CLEARANCEINCH (mm)

GH06 1/4 (6.5) GH07 1/4 (6.5) GH1 1/4 (6.5) GH2/GHS2 1/4 (6.5) GH3 1/4 (6.5) GH4 1/4 (6.5) GH6 3/8 (10)

Step 2 Remove the tool from the tool holder. Measure the diameter (d16) of the bearing surface of the tool, which is located on each side of the retaining pin groove. The minimum tool diameter is compared to a new tool bushing only. If the tool is at or below the charted value, the tool must be replaced.

MODEL

NEW TOOL DIAMETER INCH (mm)

MINIMUM TOOL DIAMETER INCH (mm)

GH06 1.63 (41.4) 1.43 (36.4) GH07 1.83 (46.6) 1.63 (41.4) GH1 2.23 (56.6) 2.02 (51.4) GH2/GHS2 2.58 (65.6) 2.38 (60.4) GH3 2.98 (75.6) 2.81 (71.4) GH4 3.37 (85.6) 3.2 (81.4) GH6 4.16 (105.6) 3.8 (96.4)

- 85 -

MAXIMUM TOOL TO TOOL BUSHING CLEARANCE Step 3 Measure the inside diameter of the lower and upper tool bushings. The maximum tool bushing inside diameter is compared to a new tool only. If the tool bushing dimensions are at or above the charted value, the bushing must be replaced.

MODEL

NEW BUSHING INSIDE DIAMETER

INCH (mm)

MAXIMUM BUSHING INSIDE DIAMETER

INCH (mm) GH06 1.67 (42.4) 1.87 (47.4) GH07 1.87 (47.4) 2.07 (52.6) GH1 2.26 (57.4) 2.46 (62.6) GH2/GHS2 2.61 (66.4) 2.82 (71.6) GH3 3.01 (76.4) 3.21 (81.6) GH4 3.40 (86.4) 3.61 (91.6) GH6 4.19 (106.4) 4.55 (115.6)

Step 4 Compare the tool and bushings to the charts in Step 2 and Step 3. Choose the new component (tool or bushing) that will bring the maximum clearance to below the value seen in the chart of Step 1. Replacing both the tool and bushings would bring the clearance back to new.

- 86 -

NPK HYDRAULIC HAMMER IMPACT BUSHINGS The impact bushing is the stop for the tool when down pressure is applied to the hydraulic hammer. In time, the impact bushing will wear through contact with the tool. The two main wear surfaces are the center bore and the beveled stop surface. The chart below gives the new and maximum dimensions. A tape measure is all that is required. You do not need a micrometer. Any measurement, at or above the maximum, requires that the impact bushing be replaced for the hammer to operate to its designed specifications. Do not weld repair the impact bushing!

IMPACT RING INSIDE DIA. - NEW (PISTON END)

d77

IMPACT RING INSIDE DIA. - MAX. (PISTON END)

d78

IMPACT RING INDENT - NEW

d79

IMPACT RING INDENT - MAX.

d80

IMPACT RING INSIDE DIA. - NEW (TOOL END)

d81

IMPACT RING INSIDE DIA. - MAX. (TOOL END)

d82

HAMMER MODEL

in mm in mm in mm in mm in mm in mm

GH06 1.26 32 1.46 37 0 0 0.2 5 1.65 42 1.85 47

GH07 1.46 37 1.65 42 0 0 0.2 5 1.85 47 2.05 52

GH1 1.77 45 1.97 50 0.19 4.8 0.39 10 2.25 57.4 2.44 62

GH2 2.05 52 2.24 57 0.18 4 0.35 9 2.68 68 2.87 73

GH3 2.36 60 2.6 65 0.37 9.5 0.59 15 3.03 77 3.22 82

GH4 2.68 68 2.87 73 0.5 12.8 0.75 19 3.4 86.4 3.58 91

GH6 3.31 84 3.5 89 0.62 15.8 0.83 21 4.19 106.4 4.37 111

- 87 -

TOOL INSPECTION 1. Deformation may occur on the tool in the retaining pin contact area (15) or thrust

surface (31). If these areas are mushroomed, the tool may become difficult to remove from the tool holder. Dress with a grinder.

2. Excessive blank hammering will cause chipping (16) in the retaining pin contact area

(15). If neglected, the chipping may reduce the life of the tool. Dress with a grinder.

3. If chipping (16) is found at the top of the tool, replace the tool. If neglected, the

piston impact surface will be damaged (AM is normal, AL needs to be replaced).

- 88 -

CHISEL TOOL RESHARPENING

Worn chisel tools can be resharpened by machining according to the dimensions below. DO NOT hardface or sharpen the tool point with a cutting torch! Resharpen only with a lathe or milling machine using sufficient coolant.

MODEL

d21 INCH MM

d16 (REF.) INCH MM

GH06 .25 6.4 1.57 40 GH07 .25 6.4 1.77 45 GH1 .38 9.7 2.17 55 GH2/GHS2 .38 9.7 2.52 64 GH3 .38 9.7 2.91 74 GH4 .50 12.7 3.31 84 GH6 .50 12.7 4.09 104

- 89 -

STANDARD LENGTH FOR NPK TOOLS

d23 = Length of tool from top to bottom. d22 = Length of tool exposed from bottom of tool bushing to end of tool. d16 = Diameter of bearing surface of tool.

NEW TOOL DIAMETER (d16)

NEW TOOL LENGTH (d23)

NEW WORKING LENGTH (d22)

MODEL

INCH MM INCH MM INCH MM GH06 1.63 41.4 19.3 490 12.2 311 GH07 1.83 46.6 20.7 527 13.1 333 GH1 2.23 56.6 23.6 599 13.6 346 GH2/GHS2 2.58 65.6 25.5 648 14.4 367 GH3 2.98 75.6 28.5 725 16.1 408 GH4 3.37 85.6 33.0 838 18 458 GH6 4.16 105.6 38.0 966 19.7 500 NOTE: Minimum tool length is determined by the depth of material penetration that is required.

- 90 -

RETAINING PIN Deformation may occur on the retaining pin in the tool contact area (AN). If this area is mushroomed, the retaining pin may become difficult to remove. Dress areas shown (AN) with a grinder.

HAMMER MODELS GH06, GH07, GH1, GH2/GHS2, GH3, GH4, GH6

- 91 -

LUBRICATION

CORRECT GREASE AND GREASE INTERVALS Proper hammer maintenance requires a sufficient supply of the correct grease to the tool (chisel). The tool must be pressed against a hard surface until it stops up inside the hammer. This prevents grease from entering piston impact area and ensures proper distribution of grease between the tool and tool bushings.

GREASE INTERVALS If the hammer is not connected to an Autolube system, see pages 93 and 94, the hammer must be greased at regular intervals to get the best life from the tool and tool bushings. There are two ways to determine grease intervals: First, grease the hammer at the beginning of the job until grease comes out between the tool and the lower tool bushing. Run the hammer until the shank of the tool starts to look dry. This determines the time interval for the greasing of this particular hammer on this particular job. Typically, this is 1 to 4 hours. Also, note the amount of grease needed to re-grease the tool. This gives you the amount of grease and how often it must be applied. An example would be that a particular hammer, on a particular job, requires half a tube of grease every 3 hours. This would be the greasing schedule you would set up. If this hammer was moved to another job, another grease schedule may have to be determined. Second, if you can’t control the grease schedule, such as rental units, then have the operator grease the hammer once every hour of hammer operation. Again, grease the hammer until grease comes out between the tool and tool bushing. This is usually more often than required, but is far cheaper than replacing prematurely worn tools and tool bushings. CORRECT GREASE The type of grease used is very important. NPK recommends a lithium soap base EP (Extreme Pressure) NLGI #2 Grease, with Moly (Molybdenum Disulfide) or other surface protecting additives. A high drop point 500° F (260° C) grease is desirable. On the following page is a list of commonly available greases, by manufacturer and brand name that meet NPK’s recommendations. NPK does not endorse any one brand as being superior to another. If you or your customers use a brand not listed, please call the NPK Service Department at 800-225-4379.

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LUBRICATION CORRECT GREASE FOR HYDRAULIC HAMMERS

MANUFACTURER BRAND NAME Amalie Oil Co. LI-2M Amoco Rykotac EP Grease Amolith Grease 94601 Rykon Premium Grease EP (Grade 94108) Rykon Premium Moly Grease (Grade 94114) Amoco Molylith Grease 92006 Amsoil, Inc. GHD BP Oil, Inc. Bearing Gard-2 Caterpillar Multipurpose Molydbenum Grease (MPGM) Cato Oil and Grease Company Moly Lithflex CX AS CITGO Citgo Extra Range Grease Conoco, Inc. Super Lube M EP #2 Dryden Oil Company Moly EP 2 Exxon Ronex Extra Duty Moly NLGI 2 Fiske Brothers Refining Co. (Lubriplate) MO-LITH No. 2 John Deere TY6333/TY6341 Moly High Temp Kendall L-424 Mobil Moly 372 Muscle Products Corporation (MPC) PL-10 Powerlift Grease LP-10 Lithium EP Plus NPK Universal Plus Lithium EP Grease Super Duty EP Grease (water resistant) Chisel Paste Pennzoil Adhezolith EP 2 Grease Phillips 66 Company Philube MW Shell Retinax ® AM Grease 71119 Retinax ® HD Grease Standard Oil Company Bearing Gard-2 Sun Refining & Marketing Company Prestige Moly 2 EP Texaco, U.S.A. Molytex EP 2 Union Oil Company Unoba Moly HD #2 Unocal Unoba Moly HD #2

- 93 -

LUBRICATION CORRECT GREASE FOR HYDRAULIC HAMMERS NPK HAMMER GREASE NPK now offers hammer grease specially formulated to meet severe job requirements. The grease is available in three different temperature ranges - 350°, 500°, and 2000°. All are compatible with Autolube systems. Universal Plus and Super Duty are lithium soap based products that resists washout and contain NPK-10 additive for surface protection in friction affected areas. Chisel Paste is an aluminum complex soap base with 12% graphite and copper additives for extreme operating conditions.

UNIVERSAL PLUS 350 deg

NPK PART NO.

14 OZ. CARTRIDGE G000-1010120 LB. KEG G000-102035 LB. PAIL G000-1030400 LB. DRUM G000-1040

SUPER DUTY 500 deg

NPK PART NO.

14 OZ. CARTRIDGE G000-1011120 LB. KEG G000-102135 LB. PAIL G000-1031400 LB. DRUM G000-1041

CHISEL PASTE 2000 deg

NPK PART NO.

14 OZ. CARTRIDGE G000-1050

AUTOLUBE SYSTEMS An automatic greasing system is recommended to reduce hammer tool and tool bushing wear. The NPK AUTOLUBE System is designed to automatically provide a continuous supply of grease to the hammer tool and tool bushing – increasing tool and tool bushing life by reducing wear. The AUTOLUBE pump is capable of pumping EP2 grease in cold weather. The pump output is adjustable according to the requirements of the hammer model and to compensate for tool bushing wear.

26 – AUTOLUBE PORT 29 – GREASE LINE 30 – GREASE FITTING FOR MANUAL LUBRICATION

- 94 -

AUTOLUBE / UNDERWATER PORT IDENTIFICATION NPK GH Series Hammers are equipped with two ports on the spacer section (J) below the main valve for use in adapting for AUTOLUBE and underwater use. The air port (17) on the left will allow the connection of an airline that will allow the hammer to be used underwater. The grease port (18), located inline with the air port, on the right will allow for AUTOLUBE connection.

- 95 -

TOOL BUSHING REPLACEMENT 1. TOOL BUSHING REMOVAL The tool bushings can be removed with either a hydraulic press or a carbon arc. CARBON ARC METHOD Drive out lock pin on lower tool bushing. NOTE: The lock pin has thread adhesive applied at assembly. Heat the pin before attempting to drive it out. Upper and lower tool bushings can be cut out with carbon arc (t12) or oxygen and acetylene (t13). Start cutting in areas ‘1’ and ‘2’ (away from the bushing retaining pin bore (19) first, and then go to areas ‘3’ and ‘4’. Care should be given not to damage the bushing retaining pin bore (19).

Use either carbon arc (t12) or cutting torch (t13) to cut bushing (G).

Exercise care when cutting to avoid damaging the tool holder. If the tool holder bore is cut accidentally, grind the surface smooth to remove sharp edges and high spots.

- 96 -

TOOL BUSHING REPLACEMENT HYDRAULIC PRESS METHOD All tool bushings may be removed with a hydraulic press. Weld a steel plate (UU) to the bushing and press out as shown.

HYDRAULIC PRESS REQUIREMENT: 100 ton minimum – All Models

- 97 -

TOOL BUSHING REPLACEMENT 2. TOOL BUSHING INSTALLATION New tool holder bushings can be installed with either a hydraulic press, or shrink

fitted with liquid nitrogen. HYDRAULIC PRESS METHOD Clean the bore of the tool holder. The surface must have no sharp edges or high spots. Grind smooth, if necessary. Apply a liberal coating of an anti-seize compound to the bushing and tool holder bore. Press the bushing all the way in. Refer to HYDRAULIC PRESS REQUIREMENT chart. HYDRAULIC PRESS REQUIREMENT: 100 ton minimum – All Models LIQUID NITROGEN METHOD Clean the bore of the tool holder. The surface must have no sharp edges or high spots. Grind smooth, if necessary.

Wear protective clothing, a safety face shield and heavy gloves!

Fill an adequately sized steel or heavy plastic bucket with liquid nitrogen. Attach two pair of vise grip type pliers to the tool bushing. Fully submerge the tool bushing for several minutes. Remove the bushing from the liquid nitrogen, after the nitrogen stops boiling. Position the bushing over the tool holder bore. The bushing should drop easily in place. Use a hand sledge and block to firmly seat the bushing.

- 98 -

TOOL HOLDER BUSHING BORE REPAIR

If the lower tool bushing bore in the tool holder becomes oversized and will no longer maintain a press fit to the tool bushing, the following repair must be made. The tool holder requires its bore to be cut oversize, then welded, then cut to original size.

1. Cut the bore oversize to Dimension d24.

DIMENSION d24 MODEL INCH MM

GH06 2.73 69.4 GH07 2.94 74.7 GH1 3.84 97.5 GH2/GHS2 4.06 103.0 GH3 4.47 113.5 GH4 4.88 124.0 GH6 5.96 151.5

2. Weld the bore undersize to Dimension d26. Pre-heat the bore to 250°F (120°C).

Use one of the following wires (or rod equivalent):

MODEL

DIMENSION d26 INCH MM

GH06 2.36 60

GH07 2.56 65

GH1 3.43 87

GH2/GHS2 3.70 94

Cronatron Cronalloy 7940 Eutectic 3010A Lincoln Lincore 33 Postal Postalloy 2892 SPL Stoody Built Up Or Equal

GH3 4.09 104

GH4 4.49 114

GH6 5.55 141

- 99 -

TOOL HOLDER BUSHING BORE REPAIR 3. Machine the bore to Dimension d25.

MODEL


GH06 2.481 63.03 2.480 63.00 GH07 2.678 68.03 2.677 68.00 GH1 3.426 87.03 3.425 87.00 GH2/GHS2 3.820 97.03 3.819 97.00 GH3 4.214 107.03 4.213 107.00 GH4 4.607 117.03 4.606 117.00 GH6 5.710 145.04 5.709 145.00

4. Dimension d27 is the diameter of the .25 (6 mm) undercut at the bottom of the

bushing bore.

MODEL


GH06 2.65 67.2 2.64 67.0 GH07 2.84 72.2 2.84 72.0 GH1 3.59 91.2 3.58 91.0 GH2/GHS2 3.98 101.1 3.97 100.9 GH3 4.38 111.2 4.37 111.0 GH4 4.77 121.2 4.76 121.0 GH6 5.87 149.2 5.87 149.0

- 100 -

TOOL HOLDER BUSHING BORE REPAIR 5. Dimension d28 is the distance from the center of the bushing retaining pin bore to

the bottom of the bushing bore. This dimension must be maintained to ensure that the retaining pin groove around the outside of the tool bushing lines up with the bushing retaining pin in the tool holder.

MODEL DIMENSION d28

INCH MM GH06 .95 24.1 .94 23.9 GH07 1.11 28.1 1.10 27.9 GH1 1.19 30.1 1.18 29.9 GH2/GHS2 1.19 30.1 1.18 29.9 GH3 1.19 30.1 1.18 29.9 GH4 1.19 30.1 1.18 29.9 GH6 1.66 42.1 1.65 41.9

- 101 -

TOOL HOLDER

REPAIR OF EXTERIOR When the hammer has been used for a long period of time, or operated with penetration of the tool holder into the material being broken, the exterior of the tool holder may become worn.

REBUILD PROCEDURE 1. Underlayment - Underlayment weld is necessary to build up the base material or

over existing hardface weld. NOTE: You cannot hardface directly over old hardfacing.

Welding Rod: Airco Austex 361, Cronatron 7770, Eutectic 3205, Postalloy 205, Stoody 2110 or equal. In Canada; NCH Canada, Inc. Hi-Pact #194 or equal.

Dry welding rod at 300°F +. Pre-heat the tool holder weld area to 150°F and maintain this temperature during the

welding operation. It is very important to maintain this temperature in cold environments.

Adjust weld current to rod manufacturer’s specification. Peen each layer. Cool slowly. Cover weld in cold environments.

2. Hardface - Hardface can only be applied over base material or underlayment weld. Never hardface existing hardface.

Welding Rod: Airco Tubecraft 1A, Cronatron 7355, Eutectic N6006, Postalloy 214, Stoody 31 or equal. In Canada; NCH Canada, Inc. Wear-X #176 or equal.

Dry welding rod at 300°F +. Pre-heat the tool holder weld area to 350°F and maintain this temperature during the

welding operation. It is very important to maintain this temperature in cold environments.

Adjust weld current to rod manufacturer’s specification. Peen each layer. Do not exceed 2-3 layers of hardface. Cool slowly. Cover weld in cold environments.

19 – RETAINING PIN BORE Leave sufficient clearance around the tool bushing retaining pin bore for removal or assembly. If necessary, a short length of 1 inch pipe can be welded in position over the hole to provide clearance. Grind flush after welding. VV – REPAIR WELDMENT (see detail)

20 – GRIND SMOOTH 21 – GRIND SMOOTH (no overlapping) WW – HARDFACING XX – UNDERLYING WELD

- 102 -

REPLACEMENT OF TIE RODS A loose tie rod is susceptible to stretching or breakage. The tie rods are designed with a locking plate to prevent the tie rod nut from turning and loosening.

PROCEDURE: If a hammer with a failed tie rod is stopped immediately, only the failed tie rod must be replaced. If the hammer has been operated with a failed tie rod for more than one hour, all four tie rods should be magna-fluxed in the thread areas to check for stress cracks caused by the 3 remaining tie rods taking the extra load created when one tie rod breaks. The following procedure is for the replacement of a single tie rod. 1. Remove all snap rings and lock plates. 2. Remove the tie rod to be replaced. 3. Discharge the gas pressure. Refer to the “DISCHARGING THE GAS PRESSURE”

section of the manual. 4. Loosen the three remaining tie rod top nuts until they are just hand tight. Do not

loosen the top nuts (R) too far, as oil maybe lost from the gas head. 5. Apply “Anti-Seize” compound on the bottom threads of the new tie rod. Assemble

into the hammer and thread into the bottom nuts.

6. Apply “Anti-Seize” compound to the top thread of the tie rod and on the washer

faces. Place the washer over the top of the tie rod. 7. Hand tighten the top nut (R). 8. Tighten the top nuts. Refer to the “TIE ROD TORQUE CHART” section of the

manual. 9. Install the lock plates. If a lock plate does not drop into place, tighten the top nut (R)

until it does. 10. Install the snap rings. 11. Gas charge the hammer. Refer to the “GAS CHARGING THE HAMMER” section of

the manual.

- 103 -

REPLACEMENT OF TIE RODS After the hammer tie rods have been torqued, install grease fittings (30) as shown. Grease until no more grease is accepted. Remove the grease fittings (30) and install plugs (TT).

- 104 -

MAXIMUM ELONGATION OF TIE RODS Tie rods may become stretched due to severe operating conditions or age in normal operating conditions. When the maximum length is reached, the tie rod must be replaced. The chart below gives the new and maximum lengths. A tape measure is all that is required.

NEW LENGTH d29 MAXIMUM LENGTH d30 MODEL INCH MM INCH MM

GH06 22.72 577 23.03 585 GH07 22.72 577 23.03 585 GH1 25.71 653 26.02 661 GH2/GHS2 27.95 710 28.27 718 GH3 30.12 765 30.43 773 GH4 36.81 935 37.13 943 GH6 43.90 1115 44.21 1123

- 105 -

TIE ROD TORQUE CHART Tighten all top nuts (R) with a torque wrench (t19) to the recommended torque specification shown below. (It may take several passes at each top nut to achieve this.) Check that no gap is noted between the sections.

Chart 1 Socket Size

MODEL

Torque

Ft/lbs (Nm)

(in)

(mm) GH06 150 (200) 1-1/16” 27 GH07 150 (200) 1-1/16” 27 GH1 185 (250) 1-1/4” 32 GH2/GHS2 295 (400) 1-7/16” 36 GH3 370 (500) 1-5/8” 41 GH4 480 (650) 1-13/16” 46 GH6 850 (1150) 2-1/2” 63

*Sweeney 503 Anti-seize recommended. If you have any questions call the NPK Service Department at 800-225-4379.

- 106 -

TORQUE VALUES FOR HAMMER FASTENERS

If hammer or hammer bracket fasteners are found to be loose, use the following charts.

Medium strength thread adhesive should be used on all the valve assembly bolts and the gas charge valve. All other bolts should be lubed with anti-seize compound.

VALVE CASE

VALVE TOP AND BOTTOM CAP

SWIVEL ADAPTER

MODEL BOLT DIA

TORQUE ft/lb (Nm)

BOLT DIA

TORQUE ft/lb (Nm)

BOLT DIA

TORQUE ft/lb (Nm)

GH06 M12 110 (150) M10 65 (85) N/A N/A GH07 M12 110 (150) M10 65 (85) N/A N/A GH1 M12 110 (150) M10 65 (85) N/A N/A

GH2/GHS2 M12 110 (150) M12 110 (150) N/A N/A GH3 M16 270 (365) M16 270 (365) M8 30 (40) GH4 M18 370 (500) M16 270 (365) M8 30 (40) GH6 M20 525 (710) M18 370 (500) M12 110 (150)

*NOTE: TORQUES OF ALL BOLTS SHOWN ARE WITH THREADS BEING LUBRICATED.

HEX SOCKET SIZE BOLT DIAMETER SOCKET HEAD CAP SCREW

M10 8mm M12 10mm M14 12mm M16 14mm M18 14mm

HAMMER BRACKET

ADAPTER BRACKET

MODEL BOLT DIA

TORQUE ft/lb (Nm)

BOLT DIA

TORQUE ft/lb (Nm)

GH06 1” 500 (678) 5/8” 165 (225) GH07 1” 500 (678) 5/8” 165 (225) GH1 1” 500 (678) 5/8” 165 (225)

GH2/GHS2 1” 500 (678) 5/8” 165 (225) GH3 1-1/4” 1000 (1356) 5/8” 165 (225) GH4 1-1/2” 1250 (1695) 5/8” 165 (225) GH6 1-1/2” 1250 (1695) 1” 550 (745)

- 107 -

MOUNTING PLATE If the hammer has been overstressed due to improper operation or installed on too large a carrier, the mounting bracket may develop a fatigue crack. EXAMPLE OF REPAIRING A CRACKED PLATE 1. Drill 3/16” (5 mm) hole through the bracket at the end of the crack to prevent further

crack propagation. 2. Grind out the crack and weld as shown. Use AWS E7016 or equivalent welding rod. 3a. For plate sizes up to 3/4” (20 mm) thick, use this weld joint:

3b. For plate sizes over 3/4” (20 mm) thick, use this weld joint:

4. Grind weld flush as shown. 22 is the direction of grinding, 23 is the direction of

principal stress.

- 108 -

WARRANTY REGISTRATION FOR NEW UNITS Complete and send to NPK after installation or complete on line at www.npkce.com. Online warranty registration can be done by the dealer or the end user.

The registration can be done in any of the following ways.

1. Mailed to: NPKCE 7550 Independence Dr. Walton Hills Ohio 44146

2. Faxed: 440-232-6294(U.S.) (+1)(440)232-6294(outside U.S.) 3. Completed on line at :

www.npkce.com The online registration can be done by the dealer or the end user. Dealers: • In the tool bar click on DEALERS. • Using your user name and password, log into the system. • At the left of the next page click on REGISTRATION. • Complete the fields with an orange diamond next to them. • At the bottom of this area, click the START REGISTRATION box and continue. • If the registration is completed online, there is no need to mail or fax the warranty

registration. End users / non NPK dealers • In the tool bar click on DEALERS • You do NOT need to fill in user name and password. • In the left column, click on the REGISTRATION. • Complete the fields with an orange diamond next to them. • At the bottom of this area, click the START REGISTRATION box and continue. • If the registration is completed online, there is no need to mail or fax the warranty

registration.

- 109 -

WARRANTY STATEMENT

- 110 -

STORAGE OF HYDRAULIC HAMMER For short term storage between jobs, place the hammer horizontal on wood blocks (t20). Be sure the tool (HH) is liberally greased and the hydraulic hoses (AO) are capped. Cover with a waterproof tarp (t21), not shown.

If the NPK HYDRAULIC HAMMER is not to be used for a long period of time (months), it is recommended the nitrogen gas be discharged through the gas charge valve (M). The tool (HH) should be removed, and the piston (not shown) pushed all the way in. Be sure the hydraulic hoses (AO) are plugged, and grease the exposed end of the piston (N). Cover with a waterproof tarp (t21), not shown.

- 111 -

DECIMAL CONVERSION CHART DECIMAL INCH TO FRACTIONS

FRACTIONS DECIMALS FRACTIONS DECIMALS 32nds 64ths 2 Place 3 Place 32nds 64ths 2 Place 3 Place

1 .02 .016 .52 .516 1 .03 .031 17 .53 .531 3 .05 .047 35 .55 .547 1/16 .06 .062 9/16 .56 .562 5 .08 .078 37 .58 .578 3 .09 .094 19 .59 .594 7 .11 .109 39 .61 .609 1/8 .12 .125 5/8 .62 .625 9 .14 .141 41 .64 .641 5 .16 .156 21 .66 .656 11 .17 .172 43 .67 .672 3/16 .19 .188 11/16 .69 .688 13 .20 .203 45 .70 .703 7 .22 .219 23 .72 .719 15 .23 .234 47 .73 .734 1/4 .25 .250 3/4 .75 .750 17 .27 .266 49 .77 .766 9 .28 .281 25 .78 .781 19 .30 .297 51 .80 .797 5/16 .31 .312 13/16 .81 .812 21 .33 .328 53 .83 .828 11 .34 .344 27 .84 .844 23 .36 .359 55 .86 .859 3/8 .38 .375 7/8 .88 .875 25 .39 .391 57 .89 .891 13 .41 .406 29 .91 .906 27 .42 .422 59 .92 .922 7/16 .44 .438 15/16 .94 .938 29 .45 .453 61 .95 .953 15 .47 .469 31 .97 .969 31 .48 .484 63 .98 .984 1/2 .50 .500 1 1.00 1.000

- 112 -

REBUILD SPECIFICATIONS CHECK SHEETS When rebuilding an NPK Hydraulic Hammer, it is necessary to inspect the piston (N), hammer body (A), “A” sleeve (O), “B” sleeve (P), cylinder spacer/impact ring (J), tool (HH), and tool bushings (F and G). Check tolerances after these components have been repaired or polished.

MEASURE CRITICAL AREAS The diagrams on the following pages show the critical locations that should be measured. Carefully measure the areas shown with bore gages and micrometers.

FAX DIMENSIONS TO NPK SERVICE DEPARTMENT Fill in the dimensions and fax this information to the NPK Service Department at (440) 232-6294 for reusability evaluation.

A. HAMMER BODY F. IMPACT BUSHING/UPPER TOOL

BUSHING G. LOWER TOOL BUSHING J. IMPACT RING/SPACER SECTION N. PISTON O. MAIN BODY “A” SLEEVE P. MAIN BODY “B” SLEEVE HH. TOOL

- 113 -

REBUILD SPECIFICATIONS CHECK SHEETS DEALER__________________________ BRANCH________________________ NAME____________________________ TITLE__________________________ TELEPHONE______________________ FAX____________________________ CUSTOMER_______________________ DATE___________________________ NPK HAMMER MODEL______________ SERIAL NO.______________________

MAIN BODY

GH06 – GH3 GH4 – GH6

REFERENCE: 1 – TOOL END, 2 – GAS END DIAMETER LENGTH

d5a d5b d5c d7

Dimensions to 0.000 inch (0.00 mm) COMMENTS: ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

- 114 -

REBUILD SPECIFICATIONS CHECK SHEETS

IMPACT BUSHING DIMENSIONS

GH06 thru GH6

d78

d80 Indentation

d82

Dimensions to 0.00 inch (0.0 mm)

COMMENTS: ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

- 115 -

REBUILD SPECIFICATIONS CHECK SHEETS

TOOL:

DIAMETER d16a d16b


GH3 thru GH6

UPPER TOOL BUSHING:___________ I.D. (d41) Dimensions to 0.00 inch (0.0 mm)

LOWER TOOL BUSHING: __________ I.D. (d41) Dimensions to 0.00 inch (0.0 mm) COMMENTS: ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

50 = STAMPING ___________________ ___________________ ___________________

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REBUILD SPECIFICATIONS CHECK SHEETS PISTON PISTON SERIAL NO.____________

REFERENCE: 1 – TOOL END, 2 – GAS END

DIAMETER LENGTH d11 d12 d10 d13


COMMENTS:

________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

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REBUILD SPECIFICATIONS CHECK SHEETS “A” SLEEVE SLEEVE SERIAL NO.____________

GH06 – GH3 GH4 – GH6

REFERENCE: 2 – GAS END INSIDE DIAMETER d45 (GH06 – GH3) d42 (GH4 – GH6)


COMMENTS: ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

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REBUILD SPECIFICATIONS CHECK SHEETS “B” SLEEVE SLEEVE SERIAL NO.____________

REFERENCE: 1 – TOOL END, 2 – GAS END INSIDE DIAMETER

d43 d44a d44b


COMMENTS: ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

FAX ALL SHEETS TO THE NPK SERVICE DEPARTMENT (440) 232-6294

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NOTES AND RECORDS NPK HYDRAULIC HAMMER MODEL NUMBER ______________________

SERIAL NUMBER_______________________ NPK INSTALLATION KIT NUMBER ________________________________ CARRIER MANUFACTURER

MODEL NUMBER

SERIES

SERIAL NUMBER

DATE OF INSTALLATION _________________ DATE OF 20 HOUR INSPECTION ______________ WARRANTY REGISTRATION SENT

SERVICE RECORD

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