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Home / Wheel Loaders / JCB Wheel Loaders / JCB 426E ZX

JCB 426E ZX Troubleshooting

The JCB 426E ZX wheel loader driveline system components: Cummins QSB6.7 6-cylinder turbocharged liquid-cooled diesel engine with a rated power of 152 hp (113 kW), and 4x3 powershift transmission. The hydraulic system has a pump with a rated capacity of 34.8 gal/min (132 l/min). The system relief pressure is 3625 psi (250 bar). The JCB 426E ZX is equipped with a power steering system, hydraulic wet disc brakes, and 20.5R25 tires. The wheel loader has a maximum lift height to hinge pin of 153.7" (3905 mm) and boom breakout force of 23830 lbs (10830 kg). The rated operating capacity is 9570 lbs (4340 kg), and tipping load is 19140 lbs (8680 kg).

Engine Troubleshooting

Diesel engine hard to start or doesn't start
Air in fuel tank - Bleed fuel tank.
Fuel filter element is clogged - Change the filter element.
Damaged or dirty injection nozzles - Inspect nozzles and replace if necessary.
Water in the fuel system - Change fuel and repair fuel system.
Valve clearance is out of adjustment - Adjust valve clearance.
Fuel injection pump is damaged - Rebuild or change fuel pump.

Diesel starts but immediately shuts off
Air cleaner is clogged - Clean or change cleaner.
Fuel filter plugging - Service or replace the filter.
Poor fuel injection pump tightness - Look for any leaks of fuel pump, tighten it fast.
Defective or clogged fuel injectors - Replace or clean fuel injectors.
Fuel injection pump failure - Repair or install new pump.

Diesel shuts off while driving
Engine is cold - Warm up the engine.
Fuel filter is plugged - Change filter element.
Air in the fuel system - Air bleeding.
Clogged or defective injection nozzles - Clean or change injection nozzles.
Improper setting of fuel injection pump timing - Check the fuel injection pump timing adjustment.

Engine stalls at low idle speed
Incorrectly adjusted low idle speed - Adjustment required.
Fuel injection pump is defective - Change pump or rebuild it.
Dirty or defective injectors - Inspect fuel injectors and change as required.
Improper valve clearance - Correct valve clearance needs to be set.

Diesel engine is losing power
Plugged air cleaner - Service or replace air cleaner.
Clogged or defective injection nozzles - Inspect nozzles and replace if necessary.
Uneven fuel injection pressure - Check the fuel injection pressure and adjust if necessary.
Incorrect valve clearance - Adjustment procedure required.
Incorrect low idle setting - Correct low idle adjustment.
Dirty fuel lines or hoses - Service fuel hoses and lines.
Cylinder head gasket is blown - Cylinder-head gasket replacement required.
Leaking or defective piston rings - Replace the piston rings as required.

Engine overheats
Insufficient coolant - Refill to the correct level and inspect system for leaks.
Lack of engine oil - Check and refill engine oil.
Radiator fins are dirty or radiator cap is defective - Install new cap or clean radiator.
Fan belt is loose or defective - Belt change is required.
Diesel engine is overloaded - Load reducing required.

Insufficient oil pressure
Engine oil insufficient - Need to add oil.
Oil filter is dirty - Service or replace engine oil filter.
Improper type of engine oil - Fill up with the correct oil viscosity.
Incorrect oil clearance in crankshaft bearing - Bearings need to be reinstalled.
Defective oil pump - Replace as required.

Engine knocking or noise
Lack of engine oil - Fill the crankcase with engine oil.
Engine is cold - Warm up the engine.
Wrong setting of fuel injection pump timing - Adjust as recommended.
Incorrect low idle speed adjustment - Test and adjust.
Clogged or defective injectors - Clean fuel injectors or change it.
Misaligned or defective connecting rod - Alignment procedure or replacement is required.
Worn or broken pistons - Replace the pistons as required.

Transmission Troubleshooting

Low transmission pressure
Transmission fluid insufficient - Add fluid to the transmission housing.
Clogged transmission fluid filter (if equipped) - Replace or service transmission fluid filter.
Relief valve is damaged - Replace relief valve.

Excessive transmission noise
Lack of transmission fluid - Add fluid to the transmission housing.
Transmission oil is dirty - Change the oil.
Backlash is incorrect or gears are damaged - Install new gears and adjust backlash properly.
Bearings are broken or worn - Change the bearings.
Damaged or worn gear shift forks - Change the shift forks.
Shaft splines are damaged or worn - Install a new shaft.

Gears are hard to shift
Gear shift linkage is corroded or worn - Lubricate or replace shift linkage.
Shift forks are worn or bent - Replace defective shift forks.
Gearshift mechanism malfunction - Identify and replace failed parts.
Worn or improperly adjusted clutch - Adjust or replace the clutch.

Transmission oil leaks
Too much fluid in transmission - Excess fluid must be drained.
Broken seals or gaskets - Install new components.

Hydraulics Troubleshooting

Hydraulic system is overheated
Hydraulic pressure incorrectly adjusted - Adjust pressure correctly.
Main relief valve is defective or unadjusted - Adjust or replace the relief valve.
Hydraulic oil is contaminated - Fill up with fresh hydraulic oil.
Lack of hydraulic oil - Add oil to the hydraulic system.
Worn hydraulic oil pump - Change or repair hydraulic pump if required.

Boom cannot be lowered or raised
Lift controls failure - Repair or replace.
Damaged hydraulic oil pump - Repair or replace pump if necessary.
Hydraulic control valve malfunction - Repair or change the valve.
Damaged hydraulic cylinder - Change or repair lift cylinder.
Hydraulic fluid level low - Checking hydraulic fluid level and add if necessary.

Bucket does not function
Faulty bucket tilt controls - Inspect and repair if necessary.
Hydraulic pump malfunction - Repair or change pump if required.
Hydraulic control valve is defective - Repair or replace the valve.
Broken bucket cylinder - Change or repair cylinder.
Insufficient hydraulic oil - Checking hydraulic oil level and add if necessary.

Bucket or lift arm moves slowly
Hydraulic pump is defective - Check pump capacity and change if necessary.
Hydraulic cylinder oil leakage - Replace cylinder piston seals.
Hydraulic oil is insufficient - Need to add oil.
Hydraulic control valve is not set properly or defective - Repair or adjust correctly.
Hydraulic pressure has dropped - Adjust it correctly.

Lift arm or bucket jerks when working
Air leaks in hydraulic system - Air bleeding is required.
Clogged hydraulic oil filter element - Clean or install new filter.
Hydraulic oil contamination - Fill up with fresh hydraulic oil.
Cylinder rod or tube is scuffed - Replace worn component.

Hydraulic pump makes excessive noise
Insufficient oil level or leaking hydraulic system - Top up hydraulic oil or remedy leakage in system.
Hydraulic filter is dirty - Service or replace hydraulic filter.
Suction line is dirty - Suction line must be serviced.
Pump sucks air - Bleed air.
Pump parts are worn out - Install new hydraulic pump or rebuild it.

Electrical Troubleshooting

Battery does not charge
Wiring connections are loose or corroded - Service or tighten cable connections.
Electrical terminal connectors are defective - Terminal connectors need to be changed.
Worn-out battery - Change the battery.
Belt is defective or loose - Adjust belt tension or install a new belt.

Starter turns slowly
Battery power is low - Recharge the battery.
Battery discharges quickly - Service charging system or install new battery.
Battery terminals are corroded or wires are disconnected - Connect cables properly or replace terminals.

Starter does not work
Battery is drained or defective - Recharge or replace battery.
Disconnected or incorrectly connected wires - Inspect battery wires and connect correctly.
Low battery output voltage - Charge the battery.
Starter motor failure - Replace or repair starter.

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WHEEL LOADERS SPECIFICATIONS

Wheel Loaders, Skid Steers, and Compact Track Loaders