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Home / Wheel Loaders / Hitachi Wheel Loaders / Hitachi ZW140-6

Hitachi ZW140-6 Troubleshooting

The Hitachi ZW140-6 wheel loader is powered by 273 cu.in (4.5L) Cummins QSB4.5 4-cylinder vertical in-line turbocharged liquid-cooled diesel engine with a rated power of 142 hp (106 kW) at 2000 rpm. The Hitachi ZW140-6 is equipped with a 4-speed hydro transmission with powershift gearbox, hydraulic power steering, hydraulic wet disc brakes, and 20.5R25 standard tires. The hydraulic system has a pump with fluid flow rate of 51.2 gpm (194 lpm). The wheel loader has a rated operating capacity of 8785 lbs (3985 kg) and tipping load of 17570 lbs (7970 kg). The max lift height is 151.2 inches (3840 mm) to hinge pin, and boom breakout force is 23850 lbs (10840 kg).

Engine Troubleshooting

Engine starts up hard or won't start
Air in fuel system - Bleed fuel system.
Fuel filter element is clogged - Clean or change the filter.
Defective or clogged injection nozzle - Replace injection nozzles.
Water or dirt in fuel system - Drain, flush, and service the system.
The valve clearance is incorrect - Have it adjusted.
Fuel injection pump malfunctioning - Repair or replace injection pump.

Diesel starts but immediately shuts off
Clogged air cleaner - Clean or replace air cleaner element.
Dirty fuel filter - Clean or change the filter.
Fuel injection pump is leaking - Repair any leaks.
Fuel injectors are dirty or defective - Inspect fuel injectors and change as required.
Fuel injection pump is not working correctly - Repair or install a new fuel pump.

Engine stops running suddenly
Engine is cold - Warm up the engine.
Fuel filter element is dirty - Replace filter element.
Air in the fuel system - Air bleeding.
Clogged injection nozzle - Replace injection nozzles.
Improper setting of fuel injection pump timing - Adjust as recommended.

Engine stalls while idling
Low idle speed set incorrectly - Need to adjust idle speed.
Fuel injection pump is defective - Repair or change injection pump.
Fuel injectors are faulty or clogged - Replace or clean fuel injectors.
Improper valve clearance - Adjustment procedure required.

Diesel engine loses power
Dirty air cleaner - Clean or change cleaner.
Fuel injection nozzles are faulty or clogged - Check and replace nozzles if required.
Insufficient fuel injection pressure - Adjust pressure to proper level.
Valve clearance is wrong - Adjust to proper valve clearance.
Low idle speed setting is incorrect - Adjust the low idle speed.
Dirty fuel lines or hoses - Fuel hoses and lines must be clean.
Blown cylinder head gasket - Install new cylinder head gasket.
Worn or broken piston rings - Install new piston rings.

Engine overheated
Engine has a lack of coolant - Add coolant fluid to cooling system and also check it for leaks.
Not enough engine oil - Fill up the engine oil.
Clogged radiator fins or damaged radiator cap - Install new cap or clean radiator.
Excessive wear of the fan belt - Belt change is required.
Diesel engine is overloaded - Reduce engine load.

Oil pressure is insufficient
Not enough oil in the engine - Fill up the engine oil.
Oil filter clogged - Change or clean engine oil filter element.
Improper type of engine oil - Use proper viscosity oil.
Main bearing oil clearance is excessive - Bearing needs to be changed.
Oil pump is defective - Inspect and change as required.

Abnormal engine knocking or noise
Lack of engine oil - Check and refill engine oil.
Coolant temperature is low - Normalize the temperature by warming up the engine.
Improper fuel injection timing - Adjust the pump as required.
Improperly adjusted low idle speed - Correct the settings.
Dirty or defective injectors - Change or clean fuel injectors.
Connecting rod is not aligned or defective - Alignment procedure or replacement is required.
Worn or scored pistons - Have pistons replaced.

Transmission Troubleshooting

Transmission fluid pressure is insufficient
Lack of transmission fluid - Checking transmission fluid level and add if necessary.
Transmission oil filter is clogged (if fitted) - Service or replace the transmission oil filter.
Defective relief valve - Replace the valve.

Transmission makes excessive noise
Low fluid level - Need to add transmission fluid.
Transmission fluid is dirty - Fill up with fresh transmission fluid.
Defective gears or improper backlash - Install new gears and set backlash correctly.
Worn or cracked bearings - Replace the bearings.
Damaged or worn gear shift forks - Replace defective shift forks.
Worn or damaged shaft splines - Replace the shaft.

Gears are hard to shift
Stuck or worn gear shift linkage - Replace or lubricate the shift linkage.
Shift forks are worn or bent - Replace the shift forks.
Gearshift mechanism is damaged - Replace or repair the mechanism.
Malfunction or incorrect clutch adjustment - Adjust or replace the clutch.

Transmission fluid leaks
High transmission fluid level - Drain the excess fluid.
Seals or gaskets are worn - Seals and gaskets replacement required.

Hydraulics Troubleshooting

Hydraulic system overheated
Hydraulic pressure incorrectly adjusted - Correct setting is required.
Defective or misadjusted main relief valve - Adjust relief valve or change if required.
Dirty hydraulic fluid - Hydraulic fluid change required.
Lack of hydraulic oil - Check oil level and add hydraulic oil as required.
Worn hydraulic oil pump - Repair or replace pump if necessary.

Boom cannot be lowered or raised
Faulty lift controls - Repair or change.
Hydraulic pump failure - Repair or replace pump if necessary.
Damaged hydraulic control valve - Replace or repair the valve.
Hydraulic cylinder malfunction - Repair or install a new lift cylinder.
Insufficient hydraulic fluid - Add fluid as required.

Bucket fails to tilt
Damaged bucket controls - Check and repair as required.
Hydraulic pump is broken - Repair or replace pump if necessary.
Damaged hydraulic control valve - Replace or repair the valve.
Damaged bucket cylinder - Replace or repair cylinder.
Low hydraulic oil level - Need to add oil.

Bucket or lift arm functions slowly
Defective hydraulic pump - Check the pump capacity and replace pump if required.
Oil leaks from hydraulic cylinder - Correct leakage by changing the seals.
Insufficient hydraulic oil - Fill the system to proper hydraulic oil level.
Damaged or incorrect adjusted hydraulic control valve - Adjust correctly or repair.
Low hydraulic pressure - Adjust it correctly.

Jerky operation of the bucket or boom
Air in hydraulic system - Need to bleed air.
Hydraulic oil filter is dirty - Replace or clean the filter.
Hydraulic fluid contamination - The fluid must be changed.
Cylinder rod or tube is scratched - Replace damaged component.

Hydraulic pump is noisy
Lack of oil or hydraulic leakage - Repair hydraulic leaks or add oil as required.
Plugged hydraulic filter - Service or replace hydraulic filter.
Suction line is clogged - Suction line must be serviced.
Air enters the pump - Bleed air.
Worn pump components - Install new hydraulic pump or rebuild it.

Electrical Troubleshooting

Battery is not charging
Wiring connections are loose or corroded - Tighten or service cable connections.
Defective battery terminal connectors - Terminal connectors need to be changed.
Bad cell in battery - Use a new battery.
Damaged or loose belt - Change belt or adjust belt tension.

Starter turns slow
Battery capacity is low - Battery is drained, recharge it.
Battery will not hold charge - Service battery or change it.
Faulty battery terminals or disconnected cables - Connect wiring properly or install new terminals.

Starter motor is not working
Battery is low or faulty - Change or recharge battery.
Battery wiring is disconnected or improperly connected - Inspect wiring and connect as required.
Battery capacity is low - Battery is drained, recharge it.
Starter motor failure - Starter should be changed.

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