Bobcat S450 Skid Steer Troubleshooting

The Bobcat S450 skid steer loader is powered by 134.1 cu.in (2.2L) Kubota V2203 M-DI-E2B 4-cylinder direct injection water-cooled diesel engine with a rated power of 46 hp (34.3 kW) at 2800 rpm. The Bobcat S450 is equipped with a single-speed or 2-speed transmission, hydraulic wet disc brakes, and 10x16.5-10 standard tires. The hydraulic system has a pump with fluid flow rate of 16.7 gpm (63.2 lpm). The hydraulic pressure is 3350 psi (231 bar). The Bobcat S450 skid steer loader has a rated operating capacity of 1340 lbs (608 kg) and tipping load of 2680 lbs (1215 kg). The lift height is 109.5" (2780 mm) to hinge pin, and dump height is 84.9" (2155 mm).

Engine Troubleshooting

Engine starts hard or won't start

There is air in the fuel system - Bleed the system.
Fuel filter element is clogged - Install new filter element.
Fuel injection nozzles are dirty or defective - Test injection nozzles and change if necessary.
Water in the fuel system - Change fuel and repair fuel system.
The valve clearance is incorrect - Have it adjusted.
Fuel injection pump is broken - Install a new pump or rebuild.

Diesel starts but immediately stops

Air filter is plugged - Change or service air filter element.
Fuel filter plugged - Replace filter element.
Fuel injection pump is leaking - Repair any leaks.
Defective or clogged fuel injectors - Clean or replace fuel injectors.
Fuel injection pump malfunction - Change pump or rebuild it.

Engine stalls after running

Engine has not warmed up to recommended temperature - Normalize the engine temperature.
Fuel filter plugging - Clean or change the filter.
Air in fuel system - Bleed fuel system.
Fuel injection nozzles are dirty or defective - Test injection nozzles and change if necessary.
Fuel injection pump timing is wrong - Set the fuel pump timing correctly.

Engine stops at low idle speed

Incorrectly adjusted low idle speed - Correct the settings.
Fuel injection pump malfunction - Install a new pump or rebuild.
Fuel injectors are dirty or defective - Test and replace fuel injectors if necessary.
The valve clearance is incorrect - Adjust valve clearance.

Engine lacks power

Air filter is clogged - Clean or replace element.
Defective or clogged injection nozzle - Test injection nozzles and change if necessary.
Incorrect fuel injection pressure - Correct the pressure settings.
The valve clearance is incorrect - Adjust valve clearance according to specifications.
Improperly adjusted low idle speed - Adjust low idling as recommended.
Restricted fuel lines or hoses - Fuel hoses and lines must be clean.
Worn cylinder head gasket - Replace the gasket as required.
Damaged or leaking piston rings - Change piston rings.

Engine overheating

Lack of coolant in cooling system - Add coolant fluid to cooling system and also check it for leaks.
Low engine oil level - Check and refill engine oil.
Defective radiator cap or clogged radiator fins - Clean radiator or replace cap.
Damaged or worn fan belt - Change the fan belt.
Engine overloaded - Load reducing is recommended.

Insufficient oil pressure

Oil level is insufficient - Fill up the engine oil.
Clogged oil filter - Clean or change engine oil filter.
Oil grade or viscosity is wrong - Drain and refill with oil of correct grade and viscosity.
Incorrect crankshaft bearing oil clearance - Install new bearings.
Oil pump is damaged - Repair or change.

Engine knocking sound or abnormal noise

Insufficient engine oil - Fill the crankcase with engine oil.
Engine not warmed up - Warm up the engine.
Wrong setting of fuel injection pump timing - Adjust the pump as required.
Too low idle RPM - Adjust the low idle speed.
Fuel injector fault - Replace fuel injectors.
Misaligned or faulty connecting rod - Connecting rod needs to be aligned or changed.
Piston wear or scoring - Replace the pistons.

Drive System Troubleshooting

Drive system does not work in either direction

Insufficient hydraulic oil - Need to add oil.
Drive chain failure - Inspect drive chain and replace defective components.
Input drive shaft is worn - Change or repair.
Relief valve malfunction - Repair or replace.
Plugged hydraulic filter or suction line - Check, clean, or replace if required.
Foot or hand controls are damaged - Repair or replace.
Drive pump or motor malfunction - Inspect and change as required.

Power is too low

Clogged hydraulic oil filter - Change or clean hydraulic filter.
Worn or open relief valve - Close or replace relief valve.
Worn or faulty transmission components - Inspect and replace defective parts.
Input drive shaft malfunction - Rebuild or change the shaft.
Air in hydraulic system - Need to bleed air.

Drive system overheats

Insufficient hydraulic fluid - Checking hydraulic fluid level and add if necessary.
Dirty hydraulic fluid filter - Check, clean, or replace as required.
Relief valve is stuck - Repair or replace relief valve.
Defective drive pump or hydraulic motor - Repair or change faulty component.
Hydraulic oil cooler is plugged - Clean cooling fins as required.
Transmission overloading - Load should be reduced.

Drive system is excessively noisy

Incorrect oil viscosity - Drain and refill with correct oil.
Air trapped in hydraulic system - Bleed air from hydraulic system.
Drive pump or hydraulic motor malfunction - Inspect and change as required.
Mechanical parts of drive system are defective or worn - Check the parts and replace if required.

Hydraulics Troubleshooting

Hydraulic system overheated

Hydraulic pressure is not correct - Correct setting is required.
Main relief valve is defective or unadjusted - Adjust relief valve or change if required.
Contaminated hydraulic fluid - Hydraulic fluid change required.
Lack of hydraulic fluid - Need to add fluid.
Faulty hydraulic oil pump - Change or repair hydraulic pump if required.

Boom can't lift or drop

Lift controls are damaged - Repair or change.
Hydraulic pump is broken - Replace or repair pump if necessary.
Hydraulic control valve is faulty - Repair or replace hydraulic valve.
Hydraulic cylinder is defective - Repair or change hydraulic cylinder.
Hydraulic fluid level low - Add fluid as required.

Bucket does not function

Bucket controls are faulty - Check and repair as required.
Hydraulic pump is broken - Repair or install new hydraulic pump.
Hydraulic control valve is faulty - Install a new hydraulic valve or repair it.
Damaged bucket cylinder - Repair or replace cylinder.
Hydraulic oil is insufficient - Need to add oil.

Boom or bucket functions slowly

Hydraulic pump is worn - Test the pump performance and change pump if required.
Oil leaks from hydraulic cylinder - Replace cylinder piston seals.
Hydraulic fluid is insufficient - Add fluid as required.
Worn or unadjusted hydraulic control valve - Repair or set correctly.
Hydraulic pressure loss - Hydraulic pressure must be set correctly.

Lift arm or bucket is working jerkily

Air in hydraulic system - Bleed air from system.
Hydraulic oil filter is dirty - Clean or install new filter.
Hydraulic oil is contaminated - Fill up with fresh hydraulic oil.
Scratched cylinder rod or tube - Replace failed component.

Hydraulic pump makes excessive noise

Hydraulic leakage or lack of oil - Refill hydraulic oil or repair leaks in system.
Plugged hydraulic filter - Service or replace hydraulic filter.
Clogged suction line - Suction line needs to be cleaned.
Air trapped in hydraulic pump - Bleed air from hydraulics.
Faulty pump parts - Install new hydraulic pump or rebuild it.

Electrical Troubleshooting

Battery won’t charge

Electrical wire connections are corroded or loose - Service or tighten connections.
Battery terminal connectors are defective - Change terminal connectors.
Faulty cell in battery - Install a new battery.
Worn or loose belt - Change belt or adjust belt tension.

Starter turns slow

Low battery output - Battery is drained, recharge it.
Battery will not hold charge - Service charging system or change battery.
Wires are disconnected or battery terminals are corroded - Check cable connections or service terminals.

Starter doesn't crank

Battery is discharged or worn - Charge or change the battery.
Battery wires are disconnected or incorrectly connected - Check wires and connect correctly.
Battery power is low - Recharge the battery.
Starter motor failing - Repair or change starter.