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Home / Wheel Loaders / JCB Wheel Loaders / JCB 406

JCB 406 Troubleshooting

The JCB 406 wheel loader is powered by 151.3 cu.in (2.5L) Kohler KDI 2504M 4-cylinder direct injection diesel engine with a rated power of 49 hp (36.4 kW) at 2600 rpm. The JCB 406 is equipped with a 2-speed hydrostatic transmission, hydraulic power steering system, hydraulic wet disc brakes, and 12.5x18 standard tires. The open center hydraulic system has a pump with fluid flow rate of 16 gpm (60.5 lpm). The hydraulic pressure is 3335 psi (230 bar). The wheel loader has a rated operating capacity of 4565 lbs (2075 kg) and tipping load of 9130 lbs (4150 kg). The max lift height is 122.8 inches (3120 mm) to hinge pin, and boom breakout force is 8185 lbs (3720 kg).

Engine Troubleshooting

Diesel engine hard to start or doesn't start
Air trapped in fuel system - Bleed air.
Dirty fuel filter - Replace filter element.
Burnt or defective injection nozzle - Replace injection nozzles.
Dirt or water in fuel system - Drain water or flush dirt from the system.
Incorrect valve clearance - Correct valve clearance needs to be set.
Damaged fuel injection pump - Repair or install new pump.

Diesel starts and suddenly stops
Dirty air cleaner - Install new air cleaner element.
Fuel filter plugging - Change filter element.
Poor fuel injection pump tightness - Look for any leaks of fuel pump, tighten it fast.
Dirty or defective injectors - Clean fuel injectors or change it.
Fuel injection pump is damaged - Rebuild or replace pump.

Engine stops suddenly during operation
Engine is not preheated - Normalize the temperature by warming up the engine.
Fuel filter element is dirty - Change filter element.
Air trapped in fuel system - Bleed air.
Clogged or defective injection nozzles - Replace injection nozzles.
Wrong setting of fuel injection pump timing - Adjust as recommended.

Engine shuts off while idling
Improperly adjusted low idle speed - Correct low idle adjustment.
Fuel injection pump is not operating properly - Repair or install new pump.
Dirty or defective injectors - Replace or clean fuel injectors.
The valve clearance is not adjusted - Correct valve clearance.

Engine power is insufficient
Clogged air cleaner - Clean or change cleaner.
Damaged or dirty injection nozzles - Clean or replace injection nozzles.
Incorrect fuel injection pressure - Correct the pressure settings.
Incorrect valve clearance - Check and adjust.
Incorrect low idle speed adjustment - Need to adjust idle speed.
Dirt in the fuel lines or hoses - Clean fuel system lines and hoses.
Cylinder head gasket defective - Install new cylinder head gasket.
Piston rings are leaking or defective - Change piston rings.

Engine overheats
Coolant level is low - Refill to the correct level and inspect system for leaks.
Engine oil level is low - Fill up the oil to required level.
Dirty radiator fins or defective radiator cap - Clean radiator or change cap.
Fan belt slipping or worn - Replace as required.
Engine is under excessive load - Load reducing is recommended.

Oil pressure too low
Low crankcase oil level - Checking oil level and add if necessary.
Clogged oil filter element - Change or service engine oil filter.
Incorrect engine oil Fill up with the proper oil viscosity.
Incorrect crankshaft bearing oil clearance - Install new bearings.
Oil pump is damaged - Remove and inspect oil pump.

Engine knocking or noise
Engine oil insufficient - Fill up the engine oil.
Low coolant temperature - Warm up to required temperature.
Fuel injection pump timing is wrong - Use the correct fuel injection pump timing adjustment.
Incorrectly set low idle speed - Adjustment required.
Dirty or defective injectors - Replace or clean fuel injectors.
Faulty or misaligned connecting rod - Replace or align connecting rod.
Broken or worn pistons - Pistons replacement required.

Hydrostatic Transmission Troubleshooting

Hydrostatic transmission makes noise
Insufficient oil level or contaminated oil - Add oil to the correct level or fill the transmission with fresh oil.
Bent or unadjusted speed control pedal linkage - Adjust or install new linkage.
Stuck relief valve - Replace the valve.
Excessive loading - Reduce the load is required.
Damaged or worn components of hydrostatic transmission - After disassembling and inspection, change defective components.

Loss of power
Lack of transmission oil supply - Fill the transmission housing with oil.
Relief valve failure - Replace relief valve as required.
Defective or not adjusted speed control pedal linkage - Adjust or change linkage.

Transmission fluid overheats
Lack of transmission oil supply - Fill the transmission housing to proper oil level.
Transmission fluid filter element is clogged - Clean or change transmission fluid filter.
Cooling components are damaged or clogged - Check all cooling components and repair or change if required.
Transmission is under excessive load - Reduce transmission load.

External fluid leaks
Seals or gaskets are worn - Replace worn gaskets or seal.
Transmission case internal pressure is too high - Repair or replace damaged components.
Oil drain line is clogged - Clean or change the line.

Hydraulics Troubleshooting

Hydraulic system is overheated
Hydraulic pressure is not adjusted correctly - Set pressure correctly.
Misadjusted or defective main relief valve - Adjust or change relief valve.
Contaminated hydraulic fluid - The fluid must be changed.
Not enough hydraulic oil in the system - Check oil level and add hydraulic oil as required.
Faulty hydraulic oil pump - Install new pump or repair it.

Lift arm cannot be raised or lowered
Damaged lift controls - Repair or change.
Defective hydraulic pump - Replace or repair pump if necessary.
Hydraulic control valve is faulty - Repair or replace the valve.
Hydraulic cylinder failure - Change or repair lift cylinder.
Hydraulic fluid is insufficient - Checking hydraulic fluid level and add if necessary.

Bucket fails to tilt
Faulty bucket tilt controls - Check and repair as required.
Hydraulic pump malfunction - Repair or replace pump if necessary.
Hydraulic control valve is defective - Repair or replace hydraulic valve.
Defective bucket cylinder - Repair or replace cylinder.
Hydraulic oil level low - Fill the system to proper hydraulic oil level.

Boom or bucket is working slowly
Worn hydraulic oil pump - Check hydraulic pump flow and replace pump if necessary.
Oil leaks from hydraulic cylinder - Install new cylinder seals.
Insufficient hydraulic fluid - Checking hydraulic fluid level and add if necessary.
Hydraulic control valve is unadjusted or worn - Repair or adjust correctly.
Low hydraulic pressure - Hydraulic pressure must be set correctly.

Jerky operation of the bucket or boom
Air leaks in hydraulic system - Bleed air from hydraulic system.
Hydraulic oil filter is dirty - Clean or change the filter.
Hydraulic oil is dirty - Change hydraulic oil.
Scored cylinder tube or rod - Change damaged component.

Excessive hydraulic pump noise
Hydraulic leakage or lack of oil - Add hydraulic oil or correct system leaks.
Hydraulic filter is dirty - Service or change hydraulic filter.
Dirty suction line - Clean suction line as required.
Air trapped in hydraulic pump - Bleed air from hydraulics.
Pump components are worn out - Rebuild or change hydraulic pump.

Electrical Troubleshooting

Battery cannot be charged
Corroded or loose cable connections - Tighten or clean electrical wiring connections.
Defective battery terminal connectors - Install new terminal connectors.
Battery is worn - Battery replacement required.
Defective or loose belt - Adjust belt tension or replace belt.

Starter cranks slowly
Low battery capacity - Charge the battery.
Battery drains quickly - Service charging system or replace battery.
Faulty battery terminals or disconnected cables - Check cable connections and replace or service terminals.

Starter will not crank
Battery is discharged or defective - Charge or replace the battery.
Wire harness is disconnected or incorrectly connected - Check wire harness and connect as required.
Battery capacity is low - Charge the battery.
Starter motor is damaged - Repair or change starter.

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WHEEL LOADERS SPECIFICATIONS

Wheel Loaders, Skid Steers, and Compact Track Loaders