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Home / Wheel Loaders / Kubota Wheel Loaders / Kubota R520

Kubota R520 Troubleshooting

The Kubota R520 wheel loader driveline system components: 134.1 cu.in (2.2L) Kubota V2203-M-E2 4-cylinder water-cooled diesel engine with a rated power of 45 hp (33.3 kW), and hydrostatic transmission. The open center hydraulic system has a pump with a rated capacity of 15.4 gal/min (58.3 l/min). The system relief pressure is 3000 psi (206 bar). The Kubota R520 is equipped with a power steering system, wet disc brakes, and 15.5/60x18 tires. The wheel loader has a maximum lift height to hinge pin of 130.3" (3310 mm) and boom breakout force of 7425 lbs (3375 kg). The rated operating capacity is 2728 lbs (1240 kg), and tipping load is 5455 lbs (2480 kg).

Engine Troubleshooting

Engine hard to start or doesn't start
Air in the fuel lines - Bleed the fuel lines.
Fuel filter element clogging - Clean or change the filter.
Fuel injection nozzles are clogged or faulty - Service or change injection nozzles.
Water in the fuel system - Change fuel and repair fuel system.
The valve clearance is incorrect - Check and adjust as required.
Defective fuel injection pump - Repair or change injection pump.

Diesel starts and stalls immediately
Air filter is dirty - Clean or change filter.
Fuel filter plugged - Replace filter element.
Fuel injection pump is leaking - Repair any leaks.
Defective or clogged fuel injectors - Replace or clean fuel injectors.
Fuel injection pump malfunctioning - Replace or repair injection pump.

Engine shuts off suddenly during operation
Engine is cold - Normalize the temperature by warming up the engine.
Fuel filter element is clogged - Change filter element.
Air in the fuel lines - Bleed the fuel lines.
Dirty or damaged injection nozzles - Check injection nozzles and replace if required.
Improper fuel injection timing - Adjust as recommended.

Engine stops while idle
Low idle speed setting is not correct - Normalize low idle speed.
Damaged fuel injection pump - Replacement or repair required.
Defective fuel injectors - Replace or clean fuel injectors.
The valve clearance is not adjusted - Check and adjust.

Diesel engine is losing power
Dirty air filter - Service or replace the air filter.
Faulty or dirty injection nozzles - Check and replace nozzles if required.
Incorrect fuel injection pressure - Check the fuel injection pressure and adjust if necessary.
The valve clearance is not adjusted - Adjust to proper valve clearance.
Low idle speed adjustment is incorrect - Normalize low idle speed.
Fuel lines or hoses are clogged - Service fuel lines and hoses.
Leaking cylinder head gasket - Replace cylinder head gasket.
Leaking or damaged piston rings - Piston rings need to be replaced.

Engine overheats
Insufficient coolant fluid - Top up coolant fluid and check system for leaks.
Engine oil level low - Check oil level and add oil as required.
Radiator fins are clogged or radiator cap is faulty - Clean radiator or change cap.
Loose or defective fan belt - Change as required.
Diesel engine is overloaded - Reduce engine load.

Oil pressure too low
Oil level is low - Add oil as required.
Oil filter element clogged - Replace or service engine oil filter.
Oil grade or viscosity is wrong - Use the specified type of engine oil.
Crankshaft bearing oil clearance is incorrect - Change bearings.
Defective oil pump - Repair or change.

Engine knocking sound or abnormal noise
Not enough engine oil - Checking oil level and add if necessary.
Engine is not warmed up to required temperature - Warm up to required temperature.
Fuel injection pump timing is wrong - Adjust fuel injection pump as required.
Low idle speed setting is incorrect - Test and adjust.
Fuel injectors are faulty or clogged - Inspect fuel injectors and change as required.
Connecting rod is misaligned or worn - Need to align or replace the connecting rod.
Worn or scored pistons - Replace the pistons as required.

Hydrostatic Transmission Troubleshooting

HST transmission noise
Low transmission oil level or contaminated oil - Add oil to the correct level or fill the transmission with fresh oil.
Speed control pedal linkage is bent or not adjusted - Adjust or change linkage.
Relief valve is damaged - Replace relief valve as required.
Excessive loading - Reduce transmission load.
Defective or worn transmission parts - Change or repair defective parts.

Lack of power
Lack of transmission fluid - Add fluid to the transmission housing.
Relief valve is damaged - Install a new relief valve.
Speed control linkage is defective or unadjusted - Replace or adjust linkage.

Hot transmission oil
Insufficient transmission fluid - Check and refill the transmission fluid.
Dirty transmission oil filter element - Service or change transmission oil filter.
Damaged or clogged cooling components - Check all cooling components and clean or replace if required.
Transmission overloaded - Load needs to be reduced.

Transmission oil leaking
Worn seals or gaskets - Change defective seal or gaskets.
High internal transmission case pressure - Change defective components.
Clogged transmission fluid return pipe - Clean or change return pipe.

Hydraulics Troubleshooting

Hydraulic system overheated
Hydraulic pressure incorrectly adjusted - Set pressure correctly.
Main relief valve is damaged or adjusted improperly - Adjust the valve or replace if necessary.
Hydraulic fluid is contaminated - Fill up with fresh hydraulic fluid.
Hydraulic oil level is low - Fill up the hydraulic oil.
Hydraulic pump is faulty - Replace or repair pump if necessary.

Lift arm fails to drop or lift
Damaged lift controls - Change or repair.
Defective hydraulic pump - Change or repair hydraulic pump if required.
Faulty hydraulic control valve - Repair or change hydraulic valve.
Hydraulic cylinder is broken - Repair or install a new lift cylinder.
Hydraulic oil level low - Check and refill the hydraulic oil.

Bucket fails to tilt
Faulty bucket tilt controls - Change or repair.
Hydraulic pump is broken - Repair or change pump if required.
Hydraulic control valve failure - Install a new hydraulic valve or repair it.
Hydraulic bucket cylinder not working - Repair or install a new cylinder.
Low hydraulic oil level - Need to add oil.

Boom or bucket is moving slowly
Hydraulic pump is faulty - Test the pump performance and change pump if required.
Hydraulic cylinder oil leakage - Install new cylinder seals.
Hydraulic oil is insufficient - Check and refill the hydraulic oil.
Damaged or incorrect adjusted hydraulic control valve - Adjust correctly or repair.
Hydraulic pressure has dropped - Adjust it correctly.

Bucket or boom is working jerkily
Air in hydraulic system - Bleed hydraulic system.
Plugged hydraulic oil filter - Clean or change the filter.
Contaminated hydraulic fluid - Hydraulic fluid change required.
Cylinder rod or tube is scratched - Change defective component.

Hydraulic pump makes excessive noise
Leaking hydraulic system or insufficient oil level - Add hydraulic oil or correct system leaks.
Clogged hydraulic filter - Clean or change the filter.
Plugged suction line - Need to clean the suction line.
Air enters the pump - Bleed air.
Worn pump components - Rebuild or change hydraulic pump.

Electrical Troubleshooting

Battery cannot be charged
Electrical cable connections are corroded or loose - Tighten or service connections.
Faulty battery terminal clamps - Install new terminal clamps.
Battery bad cell - Battery change required.
Loose or damaged belt - Adjust belt tension or replace belt.

Starter motor turns slow
Battery capacity is low - Battery is drained, recharge it.
Battery discharges quickly - Service charging system or replace battery.
Bad terminals or disconnected battery cables - Connect cables properly or replace terminals.

Starter motor is not working
Battery is discharged or worn - Battery needs to be recharged or replaced.
Wiring is incorrectly connected or disconnected - Inspect wiring and connect correctly.
Battery power is low - Charge the battery.
Starter motor failing - Replace or repair starter.

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WHEEL LOADERS SPECIFICATIONS

Wheel Loaders, Skid Steers, and Compact Track Loaders