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Gehl 4635 Troubleshooting

The Gehl 4635 skid steer loader is powered by 133 cu.in (2.2L) Deutz F3M1011F vertical inline 3-cylinder direct injection liquid-cooled diesel engine with a rated power of 44 hp (32.8 kW) at 2600 rpm. The Gehl 4635 is equipped with a radial-lift loader boom, one-speed hydrostatic transmission, 80E drive chains, and 7.00x15 or 10.00x16.5 tires. The hydraulic system has a pump with fluid flow rate of 19 gpm (72 lpm). The hydraulic pressure is 2750 psi (190 bar). The skid steer has a rated operating capacity of 1425 lbs (646 kg) and tipping load of 2850 lbs (1292 kg). The lift height is 115 inches (2920 mm) to hinge pin, and dump height is 87.2 inches (2215 mm).

Engine Troubleshooting

Engine hard to start or doesn't start
Air in the fuel system - Air bleeding.
Clogged fuel filter - Clean the filter element.
Dirty or faulty injection nozzles - Service or change injection nozzles.
Water in the fuel system - Change fuel and repair fuel system.
Valve out of adjustment - Adjust valve clearance according to specifications.
Damaged fuel injection pump - Repair or install new pump.

Engine starts but stalls suddenly
Air filter is clogged - Install new air filter element.
Fuel filter plugged - Change filter element.
Fuel injection pump has loose connections - Tighten the connections.
Fuel injectors are faulty or clogged - Replace fuel injectors.
Fuel injection pump is broken - Replace or repair injection pump.

Engine stops running suddenly
Engine is cold - Warm up to required temperature.
Fuel filter element is clogged - Replace the filter element.
Air in fuel system - Bleed fuel system.
Clogged or burnt injection nozzle - Clean or change injection nozzles.
Improper fuel injection timing - Adjust according to specifications.

Engine stalls when idling
Improperly adjusted low idle speed - Correct low idle adjustment.
Fuel injection pump is defective - Replace or rebuild injection pump.
Dirty or defective injectors - Replace fuel injectors.
Valve clearance is out of adjustment - Check and adjust as required.

Loss of engine power
Clogged air cleaner - Clean or change cleaner.
Fuel injection nozzles are faulty or clogged - Clean or change injection nozzles.
Fuel injection pressure is incorrect - Test fuel injection pressure and adjust it correctly.
Valve clearance is wrong - Need to adjust valve clearance.
Wrong adjustment of low idle speed - Normalize low idle speed.
Dirty fuel hoses or lines - Fuel hoses and lines must be clean.
Leaking cylinder head gasket - Change cylinder head gasket.
Piston rings are leaking or defective - Install new piston rings.

Engine overheating
Lack of coolant in cooling system - Top up coolant fluid and check system for leaks.
Not enough engine oil - Need to add engine oil.
Radiator core is dirty or radiator cap is damaged - Replace cap or clean radiator.
Excessive wear of the fan belt - Replace as required.
Engine overloaded - Reduce engine load.

Oil pressure is insufficient
Oil level is low - Fill crankcase to proper oil level.
Clogged oil filter - Replace or service engine oil filter.
Oil grade or viscosity is wrong - Fill up with the proper oil viscosity.
Excessive main bearing oil clearance - Bearing replacement required.
Oil pump is damaged - Check and replace if necessary.

Engine noise or knocking
Insufficient engine oil - Fill the crankcase with engine oil.
Engine is not warmed up to the required temperature - Normalize the temperature by warming up the engine.
Improper fuel injection timing - Adjust as recommended.
Incorrectly adjusted low idle speed - Adjust as required.
Fuel injector fault - Change or clean fuel injectors.
Connecting rod is not aligned or defective - Need to align or replace the connecting rod.
Worn or broken pistons - Pistons need to be replaced.

Drive System Troubleshooting

Drive system сan't work in either direction
Low hydraulic fluid level - Fill up the hydraulic fluid.
Drive chain is damaged - Inspect drive chain and replace defective components.
Defective relief valve - Rebuild or install a new relief valve.
Suction line or hydraulic filter is dirty - Service suction line or replace hydraulic filter.
Worn or damaged foot or hand controls - Inspect and repair if necessary.
Defective drive pump or motor - Replace or repair faulty component.

Low power
Plugged hydraulic oil filter - Change hydraulic filter.
Relief valve is open or defective - Replace or close relief valve.
Transmission parts are damaged or faulty - Inspect and replace defective parts.
Input drive shaft is worn - Change or repair faulty drive shaft.
Air leaks in hydraulic system - Bleed hydraulic system.

Drive system overheats
Hydraulic oil level is low - Need to add oil.
Dirty hydraulic fluid filter - Change hydraulic filter.
Defective relief valve - Change or repair relief valve.
Hydraulic motor or drive pump is defective - Change or repair faulty component.
Oil cooler is clogged - Clean the cooling fins.
Drive system is overloaded - Load should be reduced.

Drive system is noisy
Oil viscosity is wrong - Use oil of proper viscosity.
Air in the hydraulic system - Need to bleed air.
Drive pump or hydraulic motor malfunction - Repair or replace faulty component.
Mechanical components of drive system are damaged or worn - Inspect drive system and replace faulty parts.

Hydraulics Troubleshooting

Hydraulic system overheats
Hydraulic pressure is incorrect - Set pressure correctly.
Main relief valve malfunction or improper adjustment - Adjust or change relief valve.
Contaminated hydraulic fluid - Hydraulic fluid change required.
Hydraulic fluid level is insufficient - Fill the hydraulic system with oil.
Faulty hydraulic oil pump - Repair or replace pump if necessary.

Lift arm won't raise or lower
Defective lift controls - Check and repair as required.
Hydraulic pump is broken - Repair or replace pump if necessary.
Hydraulic control valve is defective - Change or repair hydraulic valve.
Hydraulic cylinder failure - Repair or change hydraulic cylinder.
Hydraulic oil level low - Need to add oil.

Bucket does not function
Bucket controls failure - Repair or change.
Hydraulic pump malfunction - Install new pump or repair it.
Hydraulic control valve malfunction - Repair or change hydraulic valve.
Defective bucket cylinder - Replace or repair cylinder.
Low hydraulic fluid level - Fill the system to proper hydraulic fluid level.

Bucket or lift arm is moving slowly
Faulty hydraulic oil pump - Check pump performance and change it if necessary.
Leaking hydraulic cylinder - Replace cylinder piston seals.
Low hydraulic fluid level - Fill the system to proper hydraulic fluid level.
Hydraulic control valve is defective or set improper - Repair or set correctly.
Hydraulic pressure is low - Adjust it correctly.

Jerky operation of the bucket or boom
Air in hydraulic system - Air bleeding is required.
Hydraulic oil filter element clogging - Change or clean oil filter.
Contaminated hydraulic oil - Change hydraulic oil.
Scored cylinder tube or rod - Replace damaged component.

Hydraulic pump makes excessive noise
Hydraulic leakage or lack of oil - Repair hydraulic leaks or add oil as required.
Hydraulic filter clogging - Clean or install new filter.
Clogged suction line - Service the suction line.
Pump sucks air - Bleed air.
Faulty pump components - Install new hydraulic pump or rebuild it.

Electrical Troubleshooting

Battery will not charge
Electrical wire connections are corroded or loose - Service or tighten cable connections.
Electrical terminal connectors are defective - Change terminal connectors.
Battery faulty cell - Battery change required.
Loose or damaged belt - Belt needs to be adjusted or changed.

Starter cranks slowly
Battery voltage is low - Battery is drained, recharge it.
Battery discharges quickly - Service battery or replace it.
Wires are disconnected or battery terminals are corroded - Connect wiring correctly or install new terminals.

Starter doesn't crank
Battery is drained or worn - Replace or charge as required.
Wiring is incorrectly connected or disconnected - Inspect wiring and connect correctly.
Battery power is low - Battery needs to be recharged.
Starter motor is damaged - Change or repair starter.