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Home / Wheel Loaders / JCB Wheel Loaders / JCB 407

JCB 407 Troubleshooting

The JCB 407 wheel loader driveline system components: 151.3 cu.in (2.5L) Kohler KDI 2504 TCR 4-cycle 4-cylinder turbocharged diesel engine with a rated power of 64 hp (48 kW), and two-range hydrostatic transmission. The hydraulic system has a pump with a rated capacity of 16 gal/min (60.5 l/min). The system relief pressure is 3335 psi (230 bar). The JCB 407 is equipped with a power steering system, hydraulic wet disc brakes, and 12.5x18 tires. The wheel loader has a maximum lift height to hinge pin of 122.8" (3120 mm) and boom breakout force of 8185 lbs (3720 kg). The rated operating capacity is 4675 lbs (2125 kg), and tipping load is 9350 lbs (4250 kg).

Engine Troubleshooting

Engine starts hard or doesn't start
Air in the fuel system - Air bleeding.
Fuel filter element is dirty - Change the filter element.
Fuel injection nozzles are faulty or clogged - Change fuel injection nozzles.
Water in the fuel system - Change fuel and repair fuel system.
Excessive valve clearance - Check and adjust as required.
Faulty fuel injection pump - Replace or rebuild injection pump.

Engine starts and stalls suddenly
Plugged air filter - Clean or change filter.
Fuel filter plugged - Install new filter element.
Fuel injection pump has loose connections - Tighten the connections.
Defective or clogged fuel injectors - Test and replace fuel injectors if necessary.
Fuel injection pump failure - Repair or change injection pump.

Engine stops unexpectedly during operation
Engine not warmed up - Warm up engine as required.
Clogged fuel filter - Install new filter element.
Air in fuel system - Bleed fuel system.
Faulty fuel injection nozzles - Change fuel injection nozzles.
Improper fuel injection timing - Set the fuel pump timing correctly.

Engine stops while idle
Low idle speed adjustment is incorrect - Adjustment required.
Fuel injection pump is damaged - Replace injection pump or repair it.
Clogged or defective injectors - Inspect fuel injectors and change as required.
Valve clearance is wrong - Have it adjusted.

Engine lacks power
Dirty air cleaner - Clean or replace air cleaner element.
Defective or clogged injection nozzle - Check and replace nozzles if required.
Fuel injection pressure is wrong - Adjust to correct pressure.
Valve clearance is wrong - Have it adjusted.
Low idle speed set incorrectly - Adjust low idle speed.
Fuel hoses or lines are dirty - Service fuel hoses and lines.
Cylinder-head gasket is leaking - Replace the gasket as required.
Defective or worn piston rings - Piston rings need to be replaced.

Engine is overheated
Lack of coolant in cooling system - Add coolant fluid and inspect the cooling system for leaks.
Low engine oil level - Fill the crankcase with engine oil.
Radiator fins are dirty or radiator cap is defective - Install new cap or clean radiator.
Loose or damaged fan belt - Belt replacement is recommended.
Diesel engine is overloaded - Reduce load on the engine.

Low oil pressure
Not enough oil in the engine - Fill up the engine oil.
Oil filter element is dirty - Service or change engine oil filter element.
Wrong oil viscosity - Use proper viscosity oil.
Crankshaft bearing has excessive oil clearance - Bearings need to be reinstalled.
Oil pump is defective - Check and replace if necessary.

Abnormal engine knocking or noise
Low engine oil level - Check and refill engine oil.
Engine is cold - Warm up engine as required.
Improper setting of fuel injection pump timing - Adjust according to specifications.
Improperly adjusted low idle speed - Adjust low idling as recommended.
Fuel injector fault - Test and replace fuel injectors if necessary.
Misaligned or faulty connecting rod - Align or replace connecting rod.
Piston wear or scoring - Replace the pistons.

Hydrostatic Transmission Troubleshooting

HST transmission noise
Low transmission oil level or contaminated oil - Add oil to proper level or pour fresh transmission oil.
Worn or out of adjustment speed control linkage - Replace or adjust linkage.
Relief valve is stuck - Change the valve.
Transmission overloaded - Load needs to be reduced.
Defective or worn transmission parts - Replace or repair defective components.

Lack of power
Transmission fluid level is low - Add fluid to the transmission housing.
Relief valve malfunction - Change the valve.
Worn or out of adjustment speed control linkage - Repair or adjust linkage.

Transmission fluid over heats
Insufficient transmission oil - Fill up the transmission oil.
Transmission oil filter is dirty - Service or change transmission oil filter.
Cooling components are defective or plugged - Inspect all cooling components and service or change if necessary.
Transmission overloaded - Reduce transmission load.

Transmission oil leaking
Seals or gaskets are broken - Change defective gaskets or seal.
High internal transmission housing pressure - Replace worn components.
Plugged transmission fluid return tube - Service or replace return tube.

Hydraulics Troubleshooting

Hydraulic system overheated
Hydraulic pressure is not correct - Adjust pressure as required.
Main relief valve is faulty or misadjusted - Adjust the valve or replace if necessary.
Hydraulic fluid contamination - Change hydraulic fluid.
Hydraulic oil level is insufficient - Add oil to the hydraulic system.
Worn hydraulic oil pump - Change or repair hydraulic pump if required.

Boom can't lift or drop
Lift controls are faulty - Replace or repair.
Hydraulic pump malfunction - Install new pump or repair it.
Hydraulic control valve failure - Install a new valve or repair it.
Defective hydraulic cylinder - Repair or change hydraulic cylinder.
Insufficient hydraulic fluid - Fill the system to proper hydraulic fluid level.

Bucket tilt does not work
Bucket tilt controls malfunction - Change or repair.
Hydraulic pump not working - Install new pump or repair it.
Hydraulic control valve malfunction - Install a new valve or repair it.
Damaged bucket cylinder - Repair or change cylinder.
Low hydraulic oil level - Need to add oil.

Boom or bucket runs slowly
Hydraulic pump is defective - Test pump performance and replace pump if necessary.
Hydraulic cylinder oil leakage - Cylinder seals need to be replaced.
Hydraulic oil is insufficient - Need to add oil.
Faulty or incorrect setting hydraulic control valve - Repair or set correctly.
Hydraulic system loosing pressure - Correct setting is required.

Lift arm or bucket is moving jerkily
Hydraulic system is leaking air - Bleed air from system.
Hydraulic oil filter element is dirty - Replace or clean the filter.
Contaminated hydraulic oil - Hydraulic oil change required.
Cylinder tube or rod scoring - Replace worn component.

Hydraulic pump makes excessive noise
Lack of oil or hydraulic leakage - Refill hydraulic oil or repair leaks in system.
Plugged hydraulic filter - Clean or replace the filter.
Plugged suction line - Need to service the suction line.
Pump sucks air - Air bleeding is required.
Pump parts are faulty - Rebuild or install new pump.

Electrical Troubleshooting

Battery cannot be charged
Corroded or loose wire connections - Clean or tighten wiring connections.
Electrical terminal connectors are faulty - Change terminal connectors.
Battery faulty cell - Install a new battery.
Belt is loose or defective - Belt needs to be adjusted or replaced.

Starter motor cranks slow
Low battery voltage - Battery is drained, recharge it.
Battery is not holding charge - Service battery or change it.
Wires are disconnected or battery terminals are corroded - Connect cables properly or replace terminals.

Starter does not work
Battery is drained or worn - Battery needs to be recharged or replaced.
Wiring harness is disconnected or improperly connected - Check wiring harness and connect as required.
Low battery voltage - Battery is drained, charge it.
Starter motor is defective - Change or repair starter.

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