vehicle maintenance presentation full

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Vehicle MaintenanceVehicle Maintenance

Prof.K.Vijayan Department of Automobile EngineeringAnna University, MIT CampusChrompet,Chennai-44

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POINTS TO BE TAKEN CARE IN ESTABLISHING AN POINTS TO BE TAKEN CARE IN ESTABLISHING AN AUTOMOBILE SERVICE STATION/ WORKSHOPAUTOMOBILE SERVICE STATION/ WORKSHOP

1. SERVICE ENTRANCE:

i The approach to service reception should be smooth.

2. RECEPTION / DIAGNOSIS (SERVICE ADVISER):

i. Warm and friendly.

ii. Careful listening to customer’s requests, correct diagnosis.

3. FILLING REPAIR ORDER AND ESTIMATES (SERVICE ADVISER):

i. Accurate preparation of repair orders.

ii. Clear explanation of work and Cost Estimate, Agreement obtained.

4. WORK ALLOCATION / INSTRUCTIONS ( FOREMAN / TECHNICIAN)

i. Work allotted for efficiency ( considering technician’s Skill level, Completion Time, Outside work Required).

ii. Accurate Work instructions ( Ex. Nature of problem, repair procedure, proper steps, completion time, etc..)

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5. REPAIRS ( TECHNICIANS)

i. Reliable work, quickly accomplished.

ii. Work performed neatly, observing proper safety rules.

6. FINAL INSPECTION ( FOREMAN / CHIEF TECHNICIAN )

i Quality of work checked ( Correct items repaired )

7. DELIVERY PREPARATION (SERVICE ADVISER)

i. Check on what work was done.

ii. Clean inside and outside vehicle.

iii. Prepare documentation.

8. DELIVERY (SERVICE ADVISER)

i. Explain details ( work done, charges, spare parts)

ii. Receive payments.

9. POST SERVICE FOLLOW UP (SERVICE ADVISER)

i. Check with customer regarding work quality.

ii. Enquire about customer satisfaction.

POINTS TO BE TAKEN CARE IN ESTABLISHING AN POINTS TO BE TAKEN CARE IN ESTABLISHING AN AUTOMOBILE SERVICE STATION/ WORKSHOPAUTOMOBILE SERVICE STATION/ WORKSHOP

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BASIC INSTRUMENTS NEEDED FOR TUNINGBASIC INSTRUMENTS NEEDED FOR TUNING FOR ENGINE:

1. Compression Gauge

2. Vacuum Gauge

3. Tachometer.

FOR IGNITION SYSTEM:

1. Power Timing light

2. Dwell meter

3. Voltmeter

4. Ohm meter

FOR ELECTRIC SYSTEM:

1. Voltmeter

2. Ammeter ( 0 to 80 A)

3. Tachometer

4. Hydrometer

5. Battery Load tester.

FOR FUEL SYTEM:

1. Fuel pump pressure Gauge

FOR EMISSION CHECKING

1. Exhaust Gas analyzer

FOR COOLING

1. Coolant Thermometer

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VEHICLE MAINTENANCEVEHICLE MAINTENANCEENGINE TUNING:

1. Loose spark plugs, start engine to blow out carbon and dust, shut –off engine and remove plugs

2. Test engine compression

3. If the compression pressure is less, perform engine service that will eliminate the trouble. If the compression is alright re-install the spark plugs

4. Remove the distributor cap, clean it, visually check for carbon tracks and corroded terminals, chips, etc. replace if not in good condition.

5. Clean and inspect distributor rotor and replace if it is not in good condition

6. Inspect the high tension leads. If they are cracked or insulation damaged, replace them

7. Check distributor centrifugal advance

8. Test the vacuum advance

< Contd. On next slide>

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ENGINE TUNING:

9. Check the distributor contact points and clean them.

10.Re-install distributor cap and replace wiring

11.Check battery state of charge, water level and hold down clamps

12.Check battery cables for damage, corrosion and loose connections

13.If the battery is over-charged or under-charged, check the dynamo (alternator) and regulator

14.Check drive belts and tighten or replace them as required

15.Check the intake manifold bolts for tightness to proper specifications. Even a slight leak will reduce engine performance

16.Check fuel lines for tight connections< Contd. On next slide>

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ENGINE TUNING:

17.Check the cooling system for leaks, weak or collapsed hoses, correct coolant level

18.Check and adjust accelerator linkage

19.Check crank-case ventilation system

20.Remove carburetor air cleaner and check choke valve. Clean or replace air filer element if necessary

21.Check and adjust contact point dwell and ignition timing

22.Adjust idle speed and mixture

23.Check the lube oil dipstick

24.Check the working of lights and horn. Adjust the head lamp for proper focusing

25.Check steering system for easiness

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STEPS INVOLVED IN SERVICING THE STEPS INVOLVED IN SERVICING THE IGNITION SYSTEM WITH CONTACT POINTSIGNITION SYSTEM WITH CONTACT POINTS

1. Clean, re-gap or replace spark plugs

2. Clean and inspect the ignition coil. If the tower (TOP) is cracked, replace the coil

3. Replace the primary wire ( coil to distributor and coil to switch) if it is broken. Make sure that the connections are clean and tight

4. Clean and inspect the distributor cap

5. Examine the rotor

6. Twist the distributor shaft in the direction or rotation and release. It should snap back. If it does not, the distributor advance mechanism must be re-paired


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STEPS INVOLVED IN SERVICING THE STEPS INVOLVED IN SERVICING THE IGNITION SYSTEM WITH CONTACT POINTSIGNITION SYSTEM WITH CONTACT POINTS

7. Inspect the contact points, replace them if necessary. Check and set the gap.

8. Put a small amount of cam lubricant ( white silicon lube ) on distributor cam.

9. Check and set the dwell using a dwell meter.

10.Adjust the timing using a timing light and tachometer

11.Check whether the advance mechanisms works using the timing light.

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SERVICING OF SPARK PLUGSSERVICING OF SPARK PLUGS

1. Remove the H.T. wire from spark plug.

To do this, slightly twist the rubber protector boot which partially covers the plug, To break the seal, grasp the boot and pull it away from the plug with steady even pressure

2. Mark each wire with the cylinder no. (use a paper tape)

3. Remove any foreign material from around the plug hole by wiping with a rag or blowing air

4. Remove the spark plugs and gaskets and keep them in order by which they are removed.

An isolated plug showing an abnormal condition indicates that the problem is with that cylinder.

5. Wipe off the exterior of the plug and inspect for proper sealing


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6. Check for burned electrodes and dirty, fouled or cracked insulators.

7. If new plugs are installed, make sure that they are of the correct type.

8. Adjust the gap if necessary by bending the ground electrode.

(use spark plug gauge)

9. To clean the plug wash it with a petroleum solvent to remove oil film

10. Dry the plug, use an abrasive type cleaner for the best cleaning job

11. Clean the threads with a wire brush

12. Blow out all abrasive particles with compressed air

13. Use a thing stiff blade to clean the space between the plug shell and insulator

14. Scrape out all carbon particles.

Turn the plug upright and shake the deposits out

Repeat until the plug is thoroughly clean.


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15. Blow out the remaining dirt with compressed air

16. Widen the plug gap by bending the ground (Side) of electrode so that an ignition point file may be inserted between the electrodes.

17. File the electrodes, until all the carbon is removed and the tip of the central electrode is flat across the top.

18. Adjust the gap to correct specification

19. Ensure that the plug seating surface in the head is clean

20. Install the plug

21. Tighten the plugs using a torque wrench to correct specification

Most 14mm plugs have torque values approx. 4kg-m< Contd. On next slide>

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22. If torque wrench is not available, tighten the plug finger tight, then using a socket wrench tighten it approx half a turn

23. Inspect the plug wires.

If insulation is cracked, soaked or brittle, replace the wire.

24. Clean the distributor cap

25. Re-install the plug wires to the same cylinder from which they were removed

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SERVICING OF THE DISTRIBUTORSERVICING OF THE DISTRIBUTOR

1. Remove the distributor cap by snapping the hold down clips

2. Inspect the cap, wipe inside of the cap.

Cracked, chipped or carbon tracked caps must be replaced.

3. If any of the metal terminals is broken or badly burned, replace the cap.

Slightly corroded or blackened terminals can be cleaned with sand paper

4. Remove the rotor, visually check for cracks, burning or corrosion of the metal tips or mechanical interference with the cap.

5. Check mechanical advance springs and counter weights.

Turn the distributor shaft in the direction of rotation and then

Release the shaft. It should snap back. If sluggish the springs are to be replaced.


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6. Check the vacuum advance

Press your fingers against the contact breaker assembly

Move the base in the direction opposite to the shaft rotation.

The base should swivel without binding.

7. Inspect the contact points for build-up and crater spots, alignment, colour and wear

Dirty points may be cleaned with a few strokes of a fine cut contact point file.

Blue burned points indicates a bad capacitor.

It is customary to replace capacitor whenever new contact points are installed.

8. Check for proper contact face alignment.


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MISALIGNMENT OF CONTACT POINTSMISALIGNMENT OF CONTACT POINTS

CONTACT POINTS CENTERED

MISALIGNMENT OF CENTRES

MISALIGNMENT OF FACES

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9. Check and adjust the point-gap.

Turn the engine until the rubbing block on the movable point is on the high point of the distributor cam lobe. This will provide the maximum point opening.

10. Measure the point gap with a feeler gauge

Change the gap to specified value by loosening the contact attachment screw

Most gap settings vary from 0.015” to 0.02”

11. Apply a single drop of distributor can lube oil to one of the cam lobes. Do not over-lubricate

12. Install the rotor and attach the distributor cap

13. If a dwell meter is available, check the dwell with the engine idling.

Re-adjust the point gap until the correct dwell reading is obtained


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COOLANT SYSTEM PROBLEMS AND CAUSESCOOLANT SYSTEM PROBLEMS AND CAUSES

ENGINE OVERHEATING:

1. Loss of Coolant

2. Defective thermostat

3. Defective Water Pump

4. Collapsed Radiator Hose

5. Excessive rust and scales

6. Obstructed air passage through radiator

7. Late Ignition Timing

8. Combustion leak into Cooling system

9. Improper coolant mix

10.Defective temperature gauge.

ENGINE RUNS TOO COOL:

1. Defective thermostat

2. Defective gauge.

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FUEL SYSTEM PROBLEMS AND CAUSESFUEL SYSTEM PROBLEMS AND CAUSES

CARBURETTOR FLOODING:

1. Worn needle and seat.

2. Leaky float.

3. Excessive Fuel pump pressure.

4. Improper float adjustment.

ROUGH IDLE:

1. Improper idle mixture.

2. Poor Compression.

3. Intake Manifold leak.

4. Defective spark plug wires.

5. Cracked distributor cap.

6. Stuck PCV valve.

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FUEL SYSTEM PROBLEMS AND CAUSESFUEL SYSTEM PROBLEMS AND CAUSES

STUMBLING DURING ACCELERATION:

1. Defective accelerator pump.

2. Improper adjustment of acceleration pump.

3. Ignition misfire.

SLUGGLISH PERFORMANCE:

1. Late ignition timing.

2. Too rich or too lean mixture

3. Defective advance mechanism.

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IGNITION SYSTEM TROUBLES AND CAUSESIGNITION SYSTEM TROUBLES AND CAUSES

ENGINE MISFIRES AT ALL SPEEDS:

1. Defective plug wires.

2. Cracked distributor cap.

3. Fouled spark plug.

4. Burned valves.

ENGINE MISFIRES DURING ACCELERATION:

1. Defective plug wires

2. Fouled or worn plugs

3. Burned contact points

4. Partially shorted contact points

5. Open capacitor

6. Poor primary circuit

7. Carburetor problems

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IGNITION SYSTEM TROUBLES AND CAUSESIGNITION SYSTEM TROUBLES AND CAUSES

ENGINE MISFIRES AT HIGH SPEEDS:

1. Insufficient dwell angle

2. Carburetor problems.

HARD STARTING:

1. Burned contact points.

2. Improper ignition timing

3. Defective ballast resistor

4. Low battery

5. Poor choke action

6. Open capacitor

7. Ignition timing too much advanced

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STARTING SYSTEM PROBLEMS AND CAUSESSTARTING SYSTEM PROBLEMS AND CAUSES

BATTERY NOT HOLDING CHARGE:

1. Internal defect of battery

2. Dirt on terminals / loose terminals

3. Electrical leakage / shorts

4. Excessive electrical usage with car stopped / idling

5. Battery not used for long periods

BATTERY ALWAYS UNDER CHARGED:

1. Defective alternator / generator

2. Low voltage regulator setting.

3. Infrequent or slow driving with heavy electrical loads

4. Excessive charging circuit resistance

5. Sulphated battery

6. Too many electrical accessories

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BATTERY USES EXCESSIVE WATER:

1. High voltage regulator setting


3. High temperature

SLOW CRANKING SPEED:

1. Excessive starter circuit resistance

2. Dragging starter armature

3. Shorted armature or field

4. Excessive engine friction

5. Worn starter brushes

STARTED SPINS WITHOUT ENGAGING:

1. Defective Bendix drive

2. Dirt or burr on starter shaft

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STARTER CLICKS WITHOUT CRANKING:

1. Defective solenoid switch

2. Open starter cable

3. Defective starter

STARTER SWITCH OR SOLENOID CHATTER:

1. Poor battery connection

2. Defective solenoid

3. Excessive starter circuit resistance

NO CRANKING, NO SOLENOID CLICK:

1. Defective starter or ignition switch

2. Broken wire solenoid or switch

3. Defective solenoid or switch

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CHARGING SYSTEM PROBLEMS AND CAUSESCHARGING SYSTEM PROBLEMS AND CAUSES

NO CHARGE RATE:

1. Defective alternator / generator

2. Defective voltage regulator

3. Open or grounded field wire

4. Open circuit

5. Worn or stuck brushes

LOW CHARGE RATE:

1. Regulator out of adjustment

2. Defective regulator

3. Excessive field circuit resistance

4. Defective alternator / regulator

5. Worn brushes

6. Sulphated battery.

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CHARGING SYSTEM PROBLEMS AND CAUSESCHARGING SYSTEM PROBLEMS AND CAUSES

HIGH CHARGE RATE:

1. Regulator out of adjustment

2. Defective regulator

3. Defective battery

4. High battery temperature

5. An accessory drawing excessive current even when the engine is not running

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PROBLEM : ENGINE WON’T STARTPROBLEM : ENGINE WON’T START

DUE TO PRIMARY CIRCUIT:

1. Burned or oxidized ignition points

2. Ballast resistor burned or open

3. Ignition points not closing

4. Breaker arm binding on pivot post, preventing closing of points

5. Breaker arm spring weak or broken

6. Breaker arm distorted or bent

7. Dirty ignition points

8. Primary lead connection loose

9. Primary winding open

10.Open ignition switch circuit

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DUE TO SHORT CIRCUITED PRIMARY CIRCUIT:

Grounded primary coil winding, grounded ignition switch or lead will cause excessive current flow and will usually cause wires to burn

POSSIBLE CAUSES FOR GROUNDED PRIMARY CIRCUIT:

1. Ignition points not opening or closing due to improper adjustment

2. Ignition points not opening due to worn rubbing block on breaker arm

3. Faulty insulating bushing on breaker arm

4. Cracked or faulty insulator at distributor primary terminal

5. Grounded condenser

6. Distributor-to-coil lead grounded

7. Primary coil winding grounded

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DUE TO FAULTY SECONDARY CIRCUIT:

1. Corroded spark plug cable terminals

2. Cracked insulation on cables (H.T.)

3. Ignition coil weak or inoperative

4. Moisture on ignition coil, terminals, distributor cover, spark plug porcelain or on distributor.

5. Improper type of spark plugs

6. Cracked distributor cap or burnt carbon brush in the cap

7. Improper connection to spark plugs ( not correct as per firing order)

8. Spark plugs damaged, dirty or wet, porcelain cracked or gaps improperly adjusted

9. Rotor contact spring bent or broken

10.Distributor rotor grounded

11.Distributor cap center terminal broken or missing

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DUE TO BATTERY:

1. Battery rundown

2. Terminal loose or badly corroded

3. Improper ground

4. Battery cable undersize

DUE TO EXCESSIVE FUEL SUPPLY ( FLOODING ):

Accumulation of liquid fuel in the inlet manifold as well as cylinder.

The engine won’t start until the rich mixture formed by flooding is pumped out

REASONS FOR FLOODING:

1. Choke not operating properly

2. Automatic choke not properly set

3. Float level not properly set

4. Dirty worn or faulty needle valve and seat

< Contd. Next slide>

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5. Float sticking or rubbing against side of fuel bowl

6. Leak in the float allowing fuel inside

7. Fuel pump pressure too high

DUE TO INSUFFICIENT FUEL SUPPLY:

1. Carburetor inlet needle stuck in its seat due to gum in fuel

2. Float level too low

3. Clogged inlet filter at carburetor

4. Faulty or insufficient capacity fuel pump

5. Fuel pump strainer closed

6. Faulty fuel pump bowl gasket

7. Flexible line twisted or restrained

8. Fuel line from tank clogged or restricted

9. Vent in fuel tank filler cap clogged or restricted

10.Worn fuel pump camshaft lobe.

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PROBLEM : HARD STARTING OF ENGINEPROBLEM : HARD STARTING OF ENGINE

WHEN THE ENGINE IS HOT:

Hard starting of the engine under hot condition is mainly due to oversupply of fuel (flooding)

In rare cases, an ignition coil may lose it’s efficiency when it is hot and cause ignition failure.

WHEN ENGINE IS COLD:

Apart form the conditions listed under the engine won’t start the following conditions are also to be checked:

1. Choke setting too lean

2. Fuel may have kerosene, water or ice

3. Ice in fuel lines

4. Engine cranked too slowly or won’t turn because:

i. Engine oil too thick in sub-zero weather

ii. Battery too weak due to very low temperature

<Contd.in next slide>

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5. Another possibility even though remote:

Water pump is jammed with ice which will interfere with the cranking of engine

Fan belt is tight

DUE TO VAPOUR LOCK:

Flow of fuel to the mixing chamber is stopped ( locked) by the formation of vaporized fuel pockets or bubbles caused by overheating the fuel by hot fuel pump, hot fuel lines or hot carburetor

High ambient temperature, hard driving, defective engine cooling and high altitudes are contributing to vapour lock.

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AFTER LONG PERIOD OF NON USAGE OF VEHICLE:

1. More volatile components in the fuel have evaporated and the remaining ones are not sufficiently volatile to form a combustible mixture

2. Low or rundown battery

3. Corrosion of engine moving parts creating high friction

4. Moving parts stuck by gummy oil

5. Engine valves stick open due to gummy deposits

These troubles are more in humid climate and near salt water

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REASONS FOR STALLING OF ENGINEREASONS FOR STALLING OF ENGINE

1. Engine idle speed set too low

2. Large air leakage in intake manifold

3. Ignition points need attention

4. Vapor lock

5. Over supply of fuel ( flooding)

6. Valves set too tight

7. Needle / seat of carburetor in-operative

8. Contaminated fuel

9. Choke sticking or improperly adjusted

10. Faulty ignition system

11. Spark plugs damp/ dirty or incorrect gap

12. In-operative distributor advance

13. Restricted exhaust system

<Contd. Next slide>

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REASONS FOR STALLING OF ENGINEREASONS FOR STALLING OF ENGINE

14. Burnt, warped or sticking valves

15. Low compression

16. Engine over heating

17. Loose or corroded wire connections

18. Incorrect idle mixture adjustment

19. Incorrect carburetor float seating

20. Leaking PCV ( if provided)

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REASONS FOR HIGH ENGINE OIL CONSUMPTIONREASONS FOR HIGH ENGINE OIL CONSUMPTION

1. External oil leaks

2. Leaky piston rings (Due to wear)

3. Leaky piston rings ( Due to sticking caused by gummy deposits).

Free the rings with suitable solvent. Blue smoke indicates badly leaking rings

4. Worn pistons and cylinders

5. Cylinder block distorted by tightening cylinder head bolts unevenly

6. Excessive clearance between the valve stems and guides

7. Worn main bearing / Con-rod bearing

8. Oil pressure too high ( wrong setting of oil pressure relief valve or clogged relief passage)

9. Loose piston pins

10. Grade of oil too light ( hard driving on hot day will also consume more oil)

<Contd. Next slide>

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REASONS FOR HIGH ENGINE OIL CONSUMPTIONREASONS FOR HIGH ENGINE OIL CONSUMPTION

11. Clogged crank case ventilation system

12. Intake manifold leak together with valve door gasket leak

13. Oil level too high

14. Piston ring gaps not staggered

15. Incorrect ring size

16. Piston rings out of round, broken or scored

17. Ring grooves or return slots clogged

18. Rings stuck in grooves

19. Compression rings installed upside down

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BATTERY PROBLEMSBATTERY PROBLEMS

BATTERY REQUIRES FREQUENT CHARGING

a) INSUFFICIENT CURRENT FLOW TO BATTERY

1. Defective generator / alternator

2. Incorrect voltage regulator setting

3. Regulator contacts oxidized or burnt


5. Corroded battery terminal

6. Regulator not grounded

7. Slipping fan belt

8. Loose connections / grounds in lighting or ignition Circuits

9. Blown regulator fuse

10. Wrong size generator rectifiers

11. Shorted or open alternator rectifiers

12. Grounded stator wire alternator

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BATTERY PROBLEMSBATTERY PROBLEMSb) EXCESSIVE STARTING LOAD CAUSING ABNORMAL CURRENT FLOW

FROM BATTERY

1. Frequent use of starter motor

2. Excessive use of starter motor ( Difficult starting)

3. Faulty starter motor

4. Excessive engine friction

c) EXCESSIVE LIGHTING LOADS

d) ABNORMAL ACCESSORY LOADS

e) INTERNAL DISCHARGE OF BATTERY

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STARTING PROBLEMSSTARTING PROBLEMS

STARTER WON’T OR ROTATES SLOWLYIt the lights become dim or go out when the starter switch is closed, the battery may be too weak to operate the starter. In this case a push cannot be push started if the battery is completely dead because alternators retain no residual magnetism.

DUE TO STARTER CIRCUIT

1. Low battery

2. Connections loose, dirty, corroded or broken at battery terminals, starter switch terminal or battery ground strap.

3. Short circuit across starter terminals.

4. Neutral start switch out of adjustment or defective

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STARTER PROBLEMSSTARTER PROBLEMS

DUE TO STARTER SWITCH1. Starter switch stuck

2. Defective solenoid

3. Starter switch makes poor contact due to dirt, corrosion, bent parts or weak parts or weak spring

4. Starter switch fails to close circuit because of sticking or broken contact parts.

5. Neutral safety switch out of adjustment of adjustment of defective. ( for cars with automatic transmission )

DUE TO ARMATURE AND FIELD CIRCUITS:

1. Armature windings burned out, shorted, grounded or open circuited.

2. Field coils burnt out, shorted or grounded.

3. Broken wire in armature winding or brush pigtail lead.

4. Loose dirty or corroded connections in field circuit.

< Contd. on next slide>

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DUE TO COMMUTATOR AND BRUSHES:

1. Brush pigtail leads loose or broken

2. Starter brushes cracked crosswise

3. Arm type brush holder sticks

4. Brush sticks in sliding brush holder

5. Bent brush holder causes poor contact

6. Starter brushes worn badly

7. Brush leads shorted or have loose, dirty, broken or corroded connections

8. Poor brush contact due to weak or broken springs

9. Brushes coated with oil

10.High ( raised) mica between commutator segments prevent brush contact

11.Commutator bars loose and / or solder melted

12.Commutator dirty, corroded or broken

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DUE TO ARMATURE BINDING:

1. Loose field poles

2. Armature shaft frozen in bearings

3. Loose end plates

4. Windings thrown out of armature slots

5. Armature locked magnetically to field poles because of loose bearing or worn/ bent shaft.

6. Bendix spring retaining screw loose and jammed against housing

7. Cracked / distorted drive housing

8. Starter misaligned

9. Jamming due to burred teeth on pinion / ring gear

10.Starter pinion ( sliding gear type) jams due to incorrect endwise clearance.

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STARTING PROBLEMSSTARTING PROBLEMS

DUE TO ENGINE RESISTANCE:

1. Piston sticking to cylinders in overheated engine

2. Pistons stuck to cylinders due to gummy oil

3. Jammed generator armature

4. Combustion chamber full of water

5. Solid ice in water pump

6. Broken engine moving parts

7. Due to cold weather and too heavy oil

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TRANSMISSION LAYOUTTRANSMISSION LAYOUT

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CLUTCH PROBLEMSCLUTCH PROBLEMSCLUTCH DRAG:

When the clutch pedal is depressed fully, the clutch disc is not completely released. As a result the clutch continues to rotate being dragged by the rotation of the engine flywheel.

Clutch drag causes clashing of gears especially when shifting from NEUTRAL to LOW or REVERSE

1. Pedal free travel ( play) is excessive. As a result pedal cannot disengage the clutch

2. Worn clutch linkage

3. Mal-adjustment of release lever

4. Clutch disc warped out of true

5. High spots on clutch facings

6. Broken or loose clutch facings

7. Loose rivets in facing

< Contd. On next slide >

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CLUTCH DRAG continued…CLUTCH DRAG continued…

8. Clutch disc hub binds on the splined clutch shaft due to bent shaft fit burred splines or splines covered with gummy oil or dirt

9. Clutch disc wobbles due to broken springs in hub

10.Clutch disc hub out of true

11.Clutch shaft bent

12.Worn out bearing ( spigot )

13.Transmission out of alignment with flywheel housing

14.Clutch pressure plate warped thus throwing release lever out of adjustment

15.Flange of clutch cover out of alignment with flywheel due to loose attaching screws, bent flange, dirt between flange and flywheel

16.Grease on clutch facing

17.Engine misaligned due to broken engine mounts

18.Loose flywheel housing to engine attaching bolts

19.Release fork pivot worn

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CLUTCH PROBLEMSCLUTCH PROBLEMSCLUTCH SLIPS:

Clutch disc slips whenever the pressure plate fails to hold it tight against the flywheel on severe slips engine speed will rise above normal on full throttle.

When there is no free play of the pedal, clutch starts slipping.

Other causes of slipping are:

1. Driving with foot resting on pedal

2. Binding or sticking of pedal or it’s linkages

3. Binding or sticking of clutch disc hub on clutch shaft

4. Binding of clutch release lever

5. Sticking of release bearing sleeve

6. Weak or broken clutch pressure springs

7. Worn clutch facings

8. Facing covered with dirt, grease or oil.

< Contd. On next slide >

51

clutch slip continued……clutch slip continued……

9. Facing burnt

10.Release levers improperly adjusted

11.Pressure plate sticks.

CLUTCH GRABS:

A clutch is said to grab when it engages too abruptly. The usual causes are:

1. Loss of tension in cushioning plates in the rim of the steel clutch disc. These plates cause the clutch facings to bulge outward slightly. The resulting springy action of the facings aid in producing a smooth, gentle clutch engagement.

2. Use of wrong type of clutch facing

3. Grease or oil on facings

4. Clutch springs too stiff

5. Momentary binding in clutch linkage while clutch being engaged

6. Exposed rivet head due to excessively worn facing or loose rivets

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clutch problems continued………clutch problems continued………

CLUTCH CHATTERS:

If a clutch chatters while it is being engaged, the trouble is caused by rapid gripping and slipping. The usual causes are:

1. Somewhat sticky clutch friction surfaces due to gummy lubricant

2. Clutch friction surfaces damp or wet

3. Weak clutch springs

4. Slight binding in clutch linkage during engagement.

5. Slight binding of pressure plate during engagement

6. Loose engine mounts.

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CLUTCH PEDAL PULSATES:

A nervous pedal when slight pressure is applied on pedal with engine running.

Pulsation will stop with more pressure on pedal. Causes are:

1. Loose or improperly adjusted engine mounts

2. Collar on clutch release sleeve does not run true due to bent clutch shaft or clutch shaft may be misaligned between crank shaft and transmission.

3. Clutch release levers not adjusted to uniform height

CLUTCH RATTLES:

This condition occurs when engine is idling with transmission neutral. Causes:

1. Excessive clearance at pressure plate driving lugs

2. Anti-rattle springs or retractor springs or release levers weak, broken or disconnected

3. Looseness in clutch pedal operating linkages

4. Loose flywheel

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NOISE WHEN CLUTCH PEDAL IS DEPRESSED:

1. Clutch release bearing dirty, worn, damaged, broken or inadequately lubricated

2. Clutch shaft bearing or bushing in crankshaft worn, damaged, broken or inadequately lubricated.

3. Clutch shaft rear bearing at front end of transmission worn, dirty or lacks lubricant

NOISE WHEN PEDAL IS RELEASED:

1. Misalignment of transmission with engine causing slight wobble of clutch disc hub. ( noticeable @ engine idling or @ LOW speeds )

2. Disc hub loose fir on splined clutch shaft

3. Disc damper springs weak or broken

4. No pedal play

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5. Weak or broaden pedal return spring

6. Weak of broken release sleeve spring

7. Clutch linkage sticks

8. Clutch pedal sticks

9. Clutch release sleeve sticks

10.Clutch release fork binds

11.Bad clutch release bearing

12.Loose flywheel

56

PROBLEMS OF GEAR BOXESPROBLEMS OF GEAR BOXESSLIPPING OF GEARS AT HIGH / SECOND GEAR (3 SPEED):

1. Gear box mounting bolts loose

2. Control rods interfere with engine mounts or clutch release lever

3. Control linkages doesn’t work freely

4. Gear does not engage fully

5. Damaged main shaft spigot bearing

6. Clutch gear bearing retainer broken or loose

7. Dirt between the Gear box housing and clutch housing

8. Misalignment of transmission

9. Worn or broken synchronizer assembly

10.Weak springs in Gear box cover

SLIPPING OF GEARS AT LOW / REVERSE GEAR:

1. First / Reverse gear damaged

2. Improperly mated splines at inside of first

57

PROBLEMS OF GEAR BOXESPROBLEMS OF GEAR BOXESSTICKING IN GEAR:

1. Clutch not releasing completely.

2. Low lubricant level

3. Corroded levers

4. Tight main drive gear spigot bearing

5. Defective synchronizer sleeve

FORWARD GEARS CLASH:

1. Clutch not releasing completely

2. Weak or broken springs in synchronizer units

3. Worn cone surfaces

NOISE IN FORWARD GEARS:

1. Insufficient or incorrect lubricant

2. Gear box misaligned

3. Main drive gear or bearings worn or damaged

4. Counter gear bearings worn or damaged

5. Synchronizer worn or damaged

58

PROBLEMS OF GEAR BOXESPROBLEMS OF GEAR BOXESHARD SHIFTING:

1. Improper clutch or adjustment

2. Worn or damaged shift links

3. Incorrect lubricant

4. Synchronizer worn or broken

JUMPING OUT OF GEAR:

1. Maladjusted, worn or loose shift linkage

2. Gear box loose or misaligned

3. Worn spigot bearing

4. Excessive end play in main drive gear

5. Bent main shaft

6. Worn or broken synchronizer

7. Detent notches worn

8. Weak detent spring

59

Gear boxGear box

60

TROUBLES WITH FULLY SYNCHRONIZED GEAR TROUBLES WITH FULLY SYNCHRONIZED GEAR BOXESBOXES

NOISES:

When diagnosing gear noise, note the gear position in which the noise occurs.

Noise in all gear positions may be due to worn or damaged constant mesh gears or bearings.

Noise in only one gear can usually be traced to the particular gear involved.

Other causes of noise are:

1. Misalignment due to loose mounting bolts

2. Clutch housing misalignment

3. Dirt or metal chips in lubricant

4. Not enough lube oil in gear box

5. Improper lubricant

61


NOISE IN ALL GEARS:

1. Incorrect lubricant level

2. Incorrect type of lubricant

3. Counter gear bearings worn or damaged

4. Counter gear worn or damaged

5. Clutch gear bearing worn or damaged

6. Main shaft bearing worn or damaged

7. Clutch gear worn or damaged

8. Transmission misalignment or loose

9. Synchronizers worn or broken

10.Main shaft gears worn or damaged

62


NOISE IN REVERSE:

1. Reverse idler gear or shaft worn or damaged

2. Reverse sliding gear worn or damaged

3. Shift linkage out of adjustment

4. Shift linkage bent or damaged

5. Shift linkage parts loose

6. Shift levers, shafts or forks worn

HARD SHIFTING:

1. Clutch pedal free travel incorrect

2. Clutch pedal parts worn or damaged

3. Incorrect type of lubricant

4. Incorrect level of lubricant

Items 3 to 6 FROM PREVIOUS SECTION

63


JUMP OUT OF GEAR:

Items 3 to 6 from “REVERSE” Section

5. Shift cover loose or gasket damaged

6. Transmission misaligned or loose

7. Synchronizers worn or broken

8. Clutch gear bearing retainer broken

9. Clutch gear bearing worn or damaged

10.Clutch spigot bearing worn or damaged

11.Main shaft worn or damaged

12.Main shaft bearing worn or damaged

64

PROPELLER SHAFT PROBLEMSPROPELLER SHAFT PROBLEMSPROBLEMS:

1. Noise

2. Vibrations

CAUSES:

1. Incorrect universal joint angles

2. Unbalanced parts

3. Loose worn out parts

4. Damaged propeller shaft tubes

Ex. Materials sticking under coating of tubes providing an unbalance

65

PROPELLER SHAFT PROBLEMSPROPELLER SHAFT PROBLEMSCHECKS:

1. Universal joint angles

2. Propeller shaft run-out

Run-out near the joint should be less than 0.01 in

Run-out near the shaft should be less than 0.015 in

A bent propeller shaft results due to accident which should be replaced

Check shaft for unbalance (can be done in garage)

3. Check looseness of all joints / parts.

4. Check every 6000 miles that the four bolts holding the propeller shaft to the rear axle are tight.

SERVICING:

1. Propeller shaft and Universal joint servicing to be done periodically

2. Cleaning and greasing of joints to be done carefully

3. Universal joints are fitted with grease nipple, grease every 3000 miles

66

PROPELLER SHAFT PROBLEMSPROPELLER SHAFT PROBLEMSTROUBLE SHOOTING:

TROUBLE CAUSE REMEDY

VIBRATION AND NOISE

a) Broken or worn bearing of universal joint spider

b) Distorted propeller shaftc) Unbalanced propeller shaftd) Loose propeller shaft

Replace

ReplaceReplaceRe-tighten

NOISE OCCURRING AT STANDING, START OR DURING COASTING

a) Worn or damaged universal joint

b) Worn propeller shaft splines, due to lack of lubrication

c) Loose propeller shaftd) Loose flanged yoke of

universal joint

Replace

Replace

Re-tightenRe-tighten

67

Differential UnitDifferential Unit

69

REAR AXLE PROBLEMSREAR AXLE PROBLEMSNOISE WHEN PULLING STRAIGHT AHEAD:

1. Not enough oil

2. Wrong grade of oil

3. Poor quality oil

4. Excessive backlash in crown wheel and pinion

5. Crown wheel (Ring gear) and pinion worn

6. Pinion shaft bearings worn or loose

7. Excessive end play for pinion shaft

8. Crown wheel and pinion mis-aligned due to bent axle housing or distorted differential case

9. Ring gear (Crown wheel) warped

10.Differential bearings worn or loose

11.Ring gear rivets or screws loose

12.Non matching ring gear and pinion

70

REAR AXLE PROBLEMSREAR AXLE PROBLEMSKNOCKING AND CLICKING:

1. Flat spot on ring gear or pinion tooth or tooth chipped or metal lodged in tooth

2. Flat spot on bearings.

3. Loose axle shaft keys

4. Loose splined shafts.

5. Mismatched differential case haves

INTERMITTENT NOISE:

1. Warped Ring gear

2. Loose ring gear rivets or screws

3. Ring gear improperly installed on differential case due to dirt or burrs between the two.

71

REAR AXLE PROBLEMSREAR AXLE PROBLEMSNOISE WHEN PULLING STRAIGHT AHEAD:

1. Not enough oil

2. Wrong grade of oil

3. Poor quality oil

4. Excessive backlash in crown wheel and pinion

5. Crown wheel (Ring gear) and pinion worn

6. Pinion shaft bearings worn or loose

7. Excessive end play for pinion shaft

8. Crown wheel and pinion mis-aligned due to bent axle housing or distorted differential case

9. Ring gear (Crown wheel) warped

10.Differential bearings worn or loose

11.Ring gear rivets or screws loose

12.Non matching ring gear and pinion

72

REAR AXLE PROBLEMSREAR AXLE PROBLEMSNOISE ON TURNS:

1. Differential planet gears or sun gears chipped broken or scuffed

2. Planet gears (Differential) binding on pinion shaft

3. Differential gears (Planet or Sun) become loose due to worn bushing or shaft

4. Excessive backlash between the differential gears

5. Excessive axle shaft end play

6. Contact surfaces between differential sun gears and case burred, scored or damaged

VIBRATION:

1. Rough rear wheel bearing

2. Unbalanced or damaged propeller shaft

3. Tire unbalance

4. Worn universal joint in propeller shaft

<Contd. in next slide>

73

REAR AXLE PROBLEMSREAR AXLE PROBLEMS5. Incorrect drive line angle

6. Improperly indexed propeller shaft at companion flange

7. Companion flange run-out too much.

OIL LEAK AT AXLE ENDS:

1. Oil level too high

2. Oil too light or poor quality

3. Axle shaft oil seals worn

4. Axle shaft bearing retainer loose

5. Cracked rear axle housing

6. Vent (if provided) clogged

74

STEERING SYSTEM PROBLEMSSTEERING SYSTEM PROBLEMSHARD STEERING:

1. Low or uneven tire pressure

2. Steering gear or connections adjusted too tight

3. Insufficient or incorrect lubricant used

4. Excessive castor

5. Suspension arms bent or twisted

6. Front spring sagged

7. Frame bent or broken

8. Steering knuckle bent

9. King pin frozen in bushing

10.Excessive misalignment of steering shaft coupling

11.Misalignment of steering column and gear

75

STEERING SYSTEM PROBLEMSSTEERING SYSTEM PROBLEMSEXCESSIVE PLAY OR LOOSENESS OF STEERING:

1. Gear connections adjusted too loose or worn

2. Steering knuckle bushing worn

3. Front wheel bearing improperly adjusted or worn

4. Worn ball joints

5. Worn or loose steering shaft bearings

6. Worn control arm bushings

7. Steering wheel loose on shaft

8. Loose linkages

9. Excessive backlash

10.Worn intermediate rod or tie-rod sockets

76

STEERING SYSTEM PROBLEMSSTEERING SYSTEM PROBLEMSPOOR RETURNABILITY:

1. Front end need lubrication

2. Too tight adjustment of steering gear

3. Front end alignment incorrect

4. Mis-alignment of steering gear to column

RATTLE OR CHUCKLE IN STEERING GEAR:

1. Insufficient or incorrect lubricant

2. Excessive back-lash

3. Worn or loose shaft bearings

4. Pitman arm loose on shaft

77

STEERING SYSTEM PROBLEMSSTEERING SYSTEM PROBLEMSVEHICLE PULLS TO ONE SIDE:

1. Low or uneven tire pressure

2. Incorrect or uneven castor or camber

3. Improperly adjusted wheel bearings

4. Uneven front height of vehicle

5. Incorrect toe-in

6. Oil or brake fluid in linings

7. Unevenly adjusted brakes

8. Frame bent or broken

9. Rear wheels not tracking front wheels

10.Loose U-bolts or sheared centre bolt or rear springs

11.Broken or weak rear springs

78

DRUM BRAKE PROBLEMSDRUM BRAKE PROBLEMSONE BRAKE DRAGS:

1. Brake hydraulic line restricted

2. Improperly adjusted or worn wheel bearings

3. Distorted or improperly adjusted brake shoe

4. Faulty retracting spring

5. Drum out of round

6. Loose back plate

7. Faulty wheel cylinder

8. Dirty brake fluid

9. Air in hydraulic system

10. Insufficient shoe to back plate lubrication

79

DRUM BRAKE PROBLEMSDRUM BRAKE PROBLEMSALL BRAKES DRAG:

1. Mechanical resistance at pedal or shoes, damaged linkages

2. Hydraulic line restricted

3. Distorted or improperly adjusted brake shoes

4. Dirty brake fluid

5. Faulty master cylinder

6. Sticking booster control valve

HARD PEDAL:

REASONS 1,2 AND 3 AS ABOVE

4. Lining glazed or worn

5. Oil and grease in lining

SPONGY PEDAL:

1. Leaks or insufficient fluid

2. Air in hydraulic system

80

TROUBLE SHOOTING OF BRAKE SYSTEMTROUBLE SHOOTING OF BRAKE SYSTEM

1. LONG PEDAL TRAVEL OR PEDAL GOES UP TO THE FLOOR:

S no. CAUSES REMEDY

1 Excessive clearance between linings and drum

Adjust the brakes

2 Weak hose Replace with new

3 Leaking wheel cylinder Service with repair kit

4 Leaking master cylinder Service with repair kit

5 Leaking stop light switch Replace

6 Air in hydraulic system Bleed the system

7 Blocked master cylinder cap-end hole

Clean and replace

8 Low fluid level in master cylinder Fill and bleed

9 Wear of brake pedal bush replace

81

TROUBLE SHOOTING OF BRAKE SYSTEMTROUBLE SHOOTING OF BRAKE SYSTEM2. SPONGY PEDAL:

S no. CAUSES REMEDY

1 Air in the hydraulic system Bleed

2 Improper lining, excessive clearance between lining and shoe

Reline

3 Distorted shoes Replace

4 Bell mouthed, worn out, weak or cracked drums

Replace the drum

5 Clogged master cylinder, filler cap vent hole

Clean or replace and bleed

6 Weak hose Replace

7 Weak master cylinder push rod and clevis

Check and strengthen master cylinder mounting

8 Bent master cylinder push rod and clevis

Replace push rod and clevis

9 Un-bedded linings ( not in full contact)

Bed linings

82


3. BRAKES PULLING (VEHICLE PULLS TO ONE SIDE):

S no. CAUSES REMEDY

1 Uneven adjustment of brakes Adjust all the brakes evenly

2 Tires improperly inflated Inflate to recommended pressure

3 Tire tread unevenly worn on either side or different types of treads

Replace with same type of tread all round

4 Grease or fluid soaked lining on the brake opposite to the direction of pulling

Replace the lining after remedying the cause of grease or fluid leak

5 Linings of different grades on either side of brake

Replace with recommended grade of linings all round

6 Un-bedded linings Bed linings< Contd. On next slide>

83


S no. CAUSES REMEDY

7 Shoes wrongly fitted Install leading and trailing shoes correctly

8 Rivets loose in lining Rivet properly

9 Wheel cylinder piston seized Service or replace wheel cylinder

10 Wheel cylinder diameter different in opposite side

Replace with correct cylinder

11 Clogged or restriction in hydraulic hose or pipe

Clean and replace pipelines

12 Weak or broken shoe return springs

Check and replace weak open coiled and cracked springs

13 Drums oval or eccentric True up or replace


84


S no. CAUSES REMEDY

14 Loose back plate mounting bolts, loose shoe abutment or adjuster housing

Tighten back plate mounting bolts and adjuster housing mountings. If abutment is loose, replace back plate.

15 Improper steering geometry Reset

16 Loose or worn tie rod end Tighten or replace

17 Loose kingpin and bushes Replace as a set

18 Loose wheel bearing, steering or U- clamp nuts

Adjust or tighten

19 Weak shock absorbers Replace

85


4. BRAKE FADE:

“FADE” is the temporary reduction of brake effectiveness resulting from heat

S no. CAUSES REMEDY

1 Incorrect grade of lining Replace with proper grade

2 Distorted shoe Replace

3 Overloaded vehicle Reduce the load

4 Dragging brakes Adjust or rectify the problem

5 Thin drums Replace

6 Contaminated fluid Change the fluid

86


5. HARD PEDAL, POOR BRAKING:

S no. CAUSES REMEDY

1 Incorrect brake adjustment Adjust properly

2 Incorrect lining Replace

3 Grease or oil soaked lining Replace lining

4 Un-bedded lining Bed lining properly

5 Glazed lining Sand paper the lining surface

6 Pedal binding on the shaft Lubricate and recondition

7 Seized master cylinder or wheel cylinder piston

Service with kit

8 Wrongly fitted shoes Install leading and trailing shoes correctly

9 Bell mouthed, barrel shaped or polished drum

Replace or re-bore the drum

87


6. REDUCED PEDAL TRAVEL:

S no. CAUSES REMEDY

1 Master cylinder recuperating hole blocked

Service the master cylinder

2 Swollen cup seal in master cylinder

Flush the system and replace all rubber pads

3 Weak shoe retracting springs Replace the springs

4 Wheel cylinder piston sticky Service and replace internal parts

5 Lining swelling Replace lining

88


8. REAR BRAKE DRAG:

S no. CAUSES REMEDY

1 Swollen ovality of drums True the drums

2 Loose drum of hub Tighten

3 Worn or loose bearing Replace or re-adjust

4 Rusty drums De-rust or replace

7. JUDDER IN PEDAL

S no. CAUSES REMEDY

1 Maladjustment Adjust

2 Parking brake cable seized Lubricate and adjust

89


9. BRAKES BINDING:

S no. CAUSES REMEDY

1 Pedal does not return fully Lubricate or recondition pedal shaft and brushes

2 No clearance between push rod and master cylinder piston

Adjust brake pedal free play

3 Improperly adjusted service brake or hand brake

Check and adjust

4 Recuperating and feed port clogged in master cylinder

Service master cylinder

5 Swollen seals Flush the system and replace all rubber pads

6 Seized wheel cylinder pistons Service and replace wheel cylinder< Contd. On next slide>

90


S no. CAUSES REMEDY

7 Improper brake fluid Replace

8 Weak or broken shoe return springs

Replace

9 Blocked filler cap vent hole Clean and replace

10.SNAPPING NOISE IN FRONT END:

S no. CAUSES REMEDY

1 Deep groves in back plate shoe pads

Replace back plate

2 Lack of lubrication in moving parts

Lubricate all moving parts on back plate with high melting point graphite grease

3 Loose drum or back plate Tighten

4 Loose or worn out front end parts Tighten or replace defective parts

91


11.ONE WHEEL DRAG:

S no. CAUSES REMEDY

1 Weak or broken retracting springs

Replace the springs

2 Clearance between the shoe and drum too small in a wheel

Adjust

3 Loose wheel bearings Adjust

4 Wheel cylinder cup seals swollen and piston seized

Service with kit

5 Excessive ovality of drum True the drum

6 Obstructed hydraulic line Clear and flush

7 Distorted shoes Replace the shoes

8 Incorrect grade of lining Replace with proper lining

92


12.BRAKE SQUEAL:

S no. CAUSES REMEDY

1 Back plate bend or shoe slightly twisted

Replace parts

2 Metallic parts or dust embedded in lining

Sandpaper the lining and drums and remove metal particles if any or replace the lining and drum if necessary

3 Loose rivets or lining not held evenly against shoe rim ( gap between lining and shoe rim)

Reline shoes properly

4 Drums not true, weak or distorted

True up or replace drums

5 Incorrect grade of lining Replace lining with recommended lining


93


S no. CAUSES REMEDY

6 Shoes scraping on back-plate shoe pads

Lubricate shoe pads with high melting point graphite grease

7 Weak or broken hold down springs

Replace defective parts

8 Loose wheel bearing Adjust bearings

9 Loose back-plate, or wheel cylinder

Tighten

10 Over adjusted steady post Adjust properly

11 Glazed lining Surface linings with sand paper

12 Highly polished drum Skim drum

94


13.THUMPING NOISE WHEN BRAKES ARE APPLIED:

S no. CAUSES REMEDY

1 Loose back-plate, drums or axle ‘U’ bolts

Tighten

2 Grabbing linings Replace with recommended grade of lining

3 Shoe retracting sprigs unequal, weak

Replace springs

4 Uneven brake drum inner diameter

Skim the drums or replace

95


14.GRINDING NOISE:

S no. CAUSES REMEDY

1 Shoe rim fouling with the drum Check shoe retracting springs for correct fit

2 Weak shoe hold down springs or bent pin

Replace parts

3 Bent shoe web Remove and replace

4 Foreign material in lining Remove and replace lining

5 Worn out or broken lining Replace with lining kit.Skim or replace drum if scored

6 Rough drum surface Skim drums

7 Improper adjustment of steady post

Adjust properly

vehicle maintenance presentation full

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