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Caterpillar 908 Troubleshooting

The Caterpillar 908 compact wheel loader driveline system components: 171 cu.in (2.8L) Caterpillar C2.8 4-cylinder turbocharged diesel engine with a rated power of 72.7 hp (54.2 kW), and hydrostatic transmission. The hydraulic system has a pump with a rated capacity of 24 gal/min (90 l/min). The system relief pressure is 3400 psi (235 bar). The Cat 908 is equipped with a power steering system, hydraulic disc brakes, and 405/70R20 tires. The wheel loader has a maximum lift height to hinge pin of 134.2" (3410 mm) and dump height of 98.8" (2510 mm). The rated operating capacity is 4070 lbs (1845 kg), and tipping load is 8140 lbs (3690 kg).

Engine Troubleshooting

Engine hard to start or won't start
Air in fuel system - Bleed fuel system.
Clogged fuel filter - Service or replace the filter.
Burnt or defective injection nozzle - Inspect nozzles and replace if necessary.
Water in the fuel system - Change fuel and repair fuel system.
The valve clearance is not adjusted - Adjustment procedure required.
Damaged fuel injection pump - Install a new pump or rebuild.

Engine starts and stops suddenly
Clogged air filter - Clean or replace element.
Fuel filter plugged - Install new filter element.
Fuel injection pump has loose connections - Tighten the connections.
Fuel injectors are dirty or defective - Replace or clean fuel injectors.
Fuel injection pump is defective - Repair or change injection pump.

Diesel shuts off while driving
Engine is cold - Warm up engine as required.
Fuel filter element is clogged - Replace filter element.
Air in fuel system - Bleed fuel system.
Dirty or faulty injection nozzles - Clean or replace injection nozzles.
Fuel injection pump timing is wrong - Check the fuel injection pump timing adjustment.

Engine shuts off while idling
Incorrect low idle setting - Adjust low idling as recommended.
Fuel injection pump malfunctioning - Change or repair the pump.
Defective fuel injectors - Replace or clean fuel injectors.
The valve clearance is not adjusted - Adjustment procedure required.

Lack of engine power
Dirty air filter - Clean or change filter.
Fuel injection nozzles are damaged - Check and replace nozzles if required.
Fuel injection pressure is wrong - Check the fuel injection pressure and adjust if necessary.
Valve out of adjustment - Adjust valve clearance.
Low idle speed setting is incorrect - Correct the settings.
Dirty fuel lines or hoses - Clean fuel system lines and hoses.
Cylinder head gasket is damaged - Gasket should be replaced.
Worn or damaged piston rings - Replace piston rings.

Engine overheats
Not enough coolant - Top up coolant fluid and check system for leaks.
Lack of engine oil - Fill the crankcase with engine oil.
Radiator core is clogged or radiator cap is leaking - Clean radiator or replace cap.
Loose or defective fan belt - Fan belt must be replaced.
Diesel engine overloaded - Reduce engine load.

Oil pressure too low
Oil level is low - Fill the crankcase with oil.
Oil filter element clogged - Change or clean engine oil filter element.
Incorrect oil viscosity - Drain crankcase and refill with correct oil.
Excessive main bearing oil clearance - Change bearings.
Oil pump is worn or damaged - Replace as required.

Engine noises or knocks
Engine oil level is insufficient - Fill up the oil to required level.
Coolant temperature is low - Warm up engine as required.
Timing of fuel injection pump is incorrect - Check the fuel injection pump timing adjustment.
Too low idle RPM - Correct low idle adjustment.
Defective fuel injectors - Change or clean fuel injectors.
Misaligned or defective connecting rod - Align or replace connecting rod.
Pistons are broken or worn - Replace the pistons as required.

Hydrostatic Transmission Troubleshooting

Hydrostatic transmission makes noise
Low transmission oil level or contaminated oil - Change transmission oil or top up to proper level.
Worn or unadjusted speed control linkage - Replace or adjust linkage.
Relief valve malfunction - Install a new relief valve.
Transmission is under excessive load - Reduce transmission load.
Damaged or worn components of hydrostatic transmission - Replace or repair defective components.

Loss of power
Insufficient transmission oil - Fill up the transmission oil.
Relief valve is damaged - Replace relief valve as required.
Speed control pedal linkage is damaged or out of adjustment - Adjust or repair linkage.

Transmission oil overheating
Insufficient transmission oil - Need to add transmission oil.
Dirty transmission fluid filter - Replace or service transmission fluid filter.
Plugged or defective cooling components - Check all cooling components and change or repair if required.
Transmission overloaded - The load should be reduced.

Transmission oil leakage
Damaged gaskets or seals - Install new components.
Internal transmission housing pressure is too high - Check transmission parts for damage or wear and replace if required.
Plugged transmission fluid return tube - Service or replace return tube.

Hydraulics Troubleshooting

Hydraulic system has overheating
Hydraulic pressure is not adjusted correctly - Set pressure correctly.
Main relief valve failure or improper setting - Adjust or replace the relief valve.
Dirty hydraulic fluid - Hydraulic fluid change required.
Not enough hydraulic fluid in the system - Need to add fluid.
Faulty hydraulic oil pump - Replace or repair pump if necessary.

Boom does not raise or lower
Damaged lift controls - Inspect and repair if necessary.
Hydraulic pump failure - Repair or replace pump if necessary.
Damaged hydraulic control valve - Change or repair hydraulic valve.
Hydraulic cylinder malfunction - Change or repair lift cylinder.
Hydraulic fluid is insufficient - Fill up the hydraulic fluid.

Bucket is not working
Bucket controls failure - Repair or replace.
Hydraulic pump malfunction - Replace or repair pump if necessary.
Damaged hydraulic control valve - Repair or change hydraulic valve.
Hydraulic bucket cylinder not working - Change or repair cylinder.
Hydraulic fluid is insufficient - Add fluid as required.

Bucket or lift arm is working slowly
Hydraulic pump is faulty - Check the pump performance and replace it if required.
Hydraulic cylinder oil leakage - Repair leak by replacing the seals.
Insufficient hydraulic fluid - Checking hydraulic fluid level and add if necessary.
Hydraulic control valve is unadjusted or worn - Repair or adjust correctly.
Hydraulic system loosing pressure - Hydraulic pressure must be set correctly.

Bucket or boom movements are jerky
Air in the hydraulic system - Air bleeding is required.
Hydraulic oil filter is clogged - Clean or replace the filter.
Hydraulic fluid is contaminated - Hydraulic fluid change required.
Scratched cylinder rod or tube - Change defective component.

Hydraulic pump is noisy
Hydraulic system leaking or not enough oil - Repair hydraulic leaks or add oil as required.
Hydraulic filter is clogged - Service or change hydraulic filter.
Suction line clogging - Suction line must be serviced.
Air in hydraulic pump - Need to bleed air.
Damaged pump parts - Change or rebuild pump.

Electrical Troubleshooting

Battery is not charging
Corroded or loose cable connections - Clean or tighten wiring connections.
Faulty battery terminal connectors - Install new terminal connectors.
Worn-out battery - Battery change required.
Belt is loose or defective - Change belt or adjust belt tension.

Starter cranks slow
Low battery output - Battery needs to be recharged.
Battery discharges quickly - Battery needs service or replacement.
Disconnected wiring or bad battery terminals - Connect cables properly or replace terminals.

Starter will not work
Battery is drained or worn - Need to charge or replace the battery.
Disconnected or improperly connected wiring harness - Inspect battery wiring harness and connect as required.
Low battery output - Charge the battery.
Starter motor failure - Replace or repair starter.

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WHEEL LOADERS SPECIFICATIONS

Caterpillar