________________________________________________________________________________

Kubota L3940 Troubleshooting

Kubota L3940 Engine Troubleshooting

Engine difficult to start or will not start: Dirty fuel filter. Replace filter element. Air in fuel system. Bleed fuel system. Fuel injection nozzles are clogged or faulty. Check and replace nozzles if required. Fuel injection pump failure. Repair or change injection pump.

Engine stalls while running: Fuel injection pump timing is not adjusted. Adjust the pump as required. Clogged fuel filter. Replace the filter element. Engine is not preheated. Engine is not warmed up to the required temperature.

Diesel starts but immediately shuts off: Fuel filter element is clogged. Clean the filter element. Fuel injection pump failure. Rebuild or replace pump. Air filter plugged. Change air filter element.

Engine is overheated: Radiator core is clogged or radiator cap is leaking. Clean radiator or install new cap. Low coolant level. Add coolant and check the components of cooling system. Fan belt is loose or defective. Belt change is required. Engine oil insufficient. Need to add engine oil.

Engine power is too low: Fuel injection nozzles are dirty or defective. Check injection nozzles and replace if required. Fuel lines or hoses are dirty. Service fuel lines and hoses. Air filter plugged. Air filter maintenance required. Defective cylinder head gasket. Replace the gasket as required.

Engine noises or knocks: Engine is not fully warmed up. Warm up to required temperature. Not enough engine oil. Need to add engine oil. Incorrect adjustment of fuel injection pump timing. Set it up as required. Piston wear or scoring. Pistons replacement required. Connecting rod is misaligned or worn. Need to change or align the connecting rod.

Engine stops while idle: Incorrectly adjusted low idle speed. Adjust as required. Improper valve clearance. Have it adjusted. Fuel injection pump malfunction. Repair or change injection pump.

Insufficient oil pressure: Engine oil level low. Fill crankcase to proper oil level. Oil pump failure. Check and replace if necessary. Plugged engine oil filter. Replace or service engine oil filter.

Kubota L3940 Transmission Troubleshooting

Transmission makes excessive noise: Damaged gears or incorrect backlash. Adjust backlash properly or replace the gears. Damaged or worn gear shift forks. Replace the shift forks. Shaft splines are stuck or worn out. Replace defective shaft. Lack of transmission fluid. Checking transmission fluid level and add if necessary. Worn or cracked bearings. Bearings need to be replaced. Transmission oil contamination. Transmission oil change required.

Gear shift is hard: Stuck or worn gear shift linkage. Lubricate or replace the shift linkage. Worn or unadjusted clutch. Adjust correctly or replace. Worn or bent gear shift forks. Shift forks need to be replaced. Gearshift mechanism is damaged. Replace or repair the mechanism.

Low transmission pressure: Insufficient transmission fluid. Add fluid to the transmission housing. Transmission oil filter element clogging (if equipped). Service or change transmission oil filter. Defective relief valve. Replace valve as required.

Transmission fluid leaking: Seals or gaskets are worn. Install new seal or gaskets. High transmission oil level. Correct the oil level.

Hydrostatic Transmission Troubleshooting

HST transmission noises: Speed control linkage is defective or unadjusted. Repair or adjust linkage. Excessive transmission load. Load needs to be reduced. Low transmission oil level or contaminated oil. Add oil to the correct level or fill the transmission with fresh oil. Relief valve is damaged. Replace the valve. Worn or defective transmission components. Check hydrostatic transmission components for defect or damage and change if necessary.

Hot transmission oil: Excessive loading. Reduce loading. Cooling components are clogged or damaged. Check all cooling components and clean or replace if required. Transmission oil level is low. Check and refill the transmission oil. Plugged transmission oil filter. Service or change transmission oil filter.

Low power: Transmission fluid insufficient. Add fluid to the transmission housing. Defective relief valve. Replace relief valve as required. Speed control pedal linkage is damaged or out of adjustment. Repair or adjust linkage.

Transmission oil leaks: Clogged transmission fluid return pipe. Clean or change return pipe. Seals or gaskets are worn. Replace worn seal or gaskets. High internal transmission case pressure. Check hydrostatic transmission components for defect or damage and change if necessary.

Kubota L3940 Hydraulic System Troubleshooting

Excessive hydraulic system heat: Improper type of hydraulic oil. Use the proper type of oil. Hydraulic fluid is dirty. Hydraulic fluid change required. Air trapped in hydraulic system. Bleed air from system. Damaged main relief valve. Relief valve replacement required.

Insufficient hydraulic fluid pressure: Low hydraulic fluid level. Checking hydraulic fluid level and add if necessary. Clogged hydraulic fluid filter. Replace hydraulic filter element or service if necessary. Hydraulic piping is leaking. Identify leaks in the system and repair it. Incorrect setting hydraulic control valve block. Set correctly. Damaged hydraulic pump. Repair or replace hydraulic fluid pump. Hydraulic cylinder is faulty. Install a new hydraulic cylinder or repair it.

Hitch not lifting or hitch lifts slowly: Hydraulic pump malfunction. Repair or replace hydraulic fluid pump. Defective main relief valve. Relief valve replacement required. Faulty hydraulic spool valve. Repair or change hydraulic valve. Hydraulic cylinder is faulty. Repair or replace hydraulic cylinder. Insufficient hydraulic fluid. Checking hydraulic fluid level and add if necessary. Clogged hydraulic oil filter element. Change the hydraulic filter element or service if required. Heavy load on the hitch. The load should be reduced.

Hitch cannot be dropped or dropping is too slow: Hydraulic cylinder not working. Install a new hydraulic cylinder or repair it. Incorrect setting hydraulic control valve. Use the correct adjustment. Damaged hitch rock shaft. Replace the shaft. Unadjusted hitch. Adjust the 3-point hitch.

Jerky lowering or lifting of the hitch: Contaminated hydraulic fluid. Change hydraulic fluid. Hydraulic pump is defective. Install a new hydraulic oil pump. Air in hydraulic pipes. Bleed hydraulic pipes. Hydraulic control valve is defective. Repair or change hydraulic valve. Hydraulic cylinder is faulty. Change or repair hydraulic cylinder.

Kubota L3940 Steering Troubleshooting

Steering wheel free play is excessive: Worn steering column shaft or coupling. Change faulty component. Steering pump malfunction. Steering pump needs to be replaced or repaired. Steering linkage components are loose or worn. Change or repair steering linkage. Faulty or worn power steering control valve. Replace or repair steering control valve as required.

Steering is stiff: Air trapped inside steering system. Bleed the steering system. Steering filter is clogged. Steering filter maintenance required. Steering fluid level is insufficient. Add oil to steering system. Faulty or worn power steering control valve. Repair or change the steering control valve. Steering pump is worn. Steering pump needs to be repaired or replaced. Stuck or damaged steering pump control valve. Replace or clean flow control valve. Incorrectly mounted or defective steering column. Mount the steering column correctly or replace it. Uneven tire pressure. Inflate the tires properly. Not adjusted toe-in. Check and adjust toe-in. Steering cylinder is leaking. Replace worn cylinder seals or scratched piston rod.

Front wheels wander to left or right: Defective or worn power steering control valve. Repair or change the steering control valve. Defective steering cylinder. Replace or repair hydraulic steering cylinder. Improper toe-in. Check and adjust toe-in. Steering linkage components are loose or worn. Check and change as required. Improperly adjusted or defective front wheel bearings. Adjust correctly or change bearings. Front tyres wear unevenly. Change the tyres.

Kubota L3940 Electrical Troubleshooting

Battery won’t charge: Corroded or loose cable connections. Clean or tighten wiring connections. Faulty battery terminal clamps. Terminal clamps need to be replaced. Battery faulty cell. Replace the battery. Defective or loose belt. Need to adjust belt tension or replace belt.

Starter cranks slowly: Low battery output voltage. Recharge the battery. Battery won’t hold charge. Service battery or change it. Battery cables are disconnected or terminals are faulty. Check battery wires and service or replace terminals.

Starter is not cranking: Battery is discharged or defective. Charge or change the battery. Disconnected or incorrectly connected wires. Inspect battery wires and connect correctly. Battery power is low. Low battery charging, charge as required. Faulty starter motor. Repair or replace starter.