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Bobcat S630 Troubleshooting

The Bobcat S630 skid steer loader driveline system components: a 203.2 cu.in (3.3L) Kubota V3307 four-cylinder turbocharged diesel engine with a rated power of 74.3 hp (55.4 kW), and 1-speed or 2-speed transmission. The hydraulic system has a pump with a rated capacity of 23 gal/min (87.1 l/min). The system relief pressure is 3500 psi (241 bar). The Bobcat S630 is equipped with a radial-lift loader boom, 120 HSOC roller chains, and 12x16.5 or 33-15.5x16.5 tires. The skid steer has a boom lifting force of 3990 lbs (1814 kg) and bucket breakout force of 4340 lbs (1973 kg). The rated operating capacity is 2180 lbs (990 kg), and tipping load is 4360 lbs (1980 kg).

Engine Troubleshooting

Engine difficult to start or will not start
Air in the fuel system - Air bleeding.
Fuel filter plugged - Clean the filter element.
Damaged or dirty injection nozzles - Replace injection nozzles.
Dirt or water in fuel system - Drain water or flush dirt from the system.
Valve clearance is wrong - Need to adjust valve clearance.
Damaged fuel injection pump - Install a new fuel pump or repair.

Diesel starts and suddenly stops
Air filter is dirty - Change or service air filter element.
Fuel filter element is dirty - Service or replace the filter.
Fuel injection pump has loose connections - Tighten the connections.
Defective or clogged fuel injectors - Test and replace fuel injectors if necessary.
Fuel injection pump malfunctioning - Replace or rebuild injection pump.

Engine shuts off suddenly while running
Low coolant temperature - Normalize the temperature by warming up the engine.
Fuel filter plugging - Install new filter element.
Air trapped in fuel system - Bleed air.
Defective injection nozzle - Inspect nozzles and replace if necessary.
Incorrect adjustment of fuel injection pump timing - Use the correct fuel injection pump timing adjustment.

Engine stops while idle
Low idle speed set incorrectly - Test and adjust.
Fuel injection pump is damaged - Replace injection pump or repair it.
Defective fuel injectors - Inspect fuel injectors and change as required.
The valve clearance is incorrect - Correct valve clearance.

Low engine power
Dirty air filter - Service or replace the air filter.
Faulty or dirty injection nozzles - Test injection nozzles and change if necessary.
Improper fuel injection pressure - Correct the pressure settings.
Incorrect valve clearance - Adjust valve clearance according to specifications.
Low idle speed setting is not correct - Test and adjust.
Fuel lines or hoses are dirty - Clean fuel system lines and hoses.
Cylinder-head gasket is leaking - Install new cylinder head gasket.
Piston rings are worn or defective - Piston rings replacement required.

Engine is overheated
Insufficient coolant - Add coolant fluid to cooling system and also check it for leaks.
Lack of engine oil - Add oil to the engine crankcase.
Damaged radiator cap or dirty radiator core - Clean radiator or install new cap.
Excessive wear of the fan belt - Belt change is required.
Engine is under excessive load - Reduce load on the engine.

Oil pressure is low
Low oil level - Check and refill the oil.
Oil filter element clogging - Change or service engine oil filter.
Oil grade or viscosity is incorrect - Use oil of proper viscosity.
Excessive main bearing oil clearance - Replace bearings.
Oil pump malfunction - Repair or replace.

Engine noise or knocking
Engine oil level low - Fill up the oil to required level.
Low coolant temperature - Warm up the engine.
Improper fuel injection timing - Set the fuel pump timing correctly.
Low idle speed setting is not correct - Correct low idle adjustment.
Fuel injector fault - Inspect fuel injectors and change as required.
Connecting rod is not aligned or worn - Connecting rod needs to be aligned or changed.
Pistons are broken or worn - Replace the pistons.

Drive System Troubleshooting

Machine will not move forward or backward
Hydraulic oil is insufficient - Checking hydraulic oil level and add if necessary.
Drive chain malfunction - Check drive chain and change faulty parts.
Defective input drive shaft - Rebuild or change.
Stuck relief valve - Service or change relief valve.
Dirty hydraulic filter or suction line - Check, clean, or change if necessary.
Faulty foot or hand controls - Inspect and repair if necessary.
Worn drive motor or pump - Change or repair faulty component.

Power is too low
Hydraulic oil filter is dirty - Change or clean hydraulic filter.
Relief valve is defective or opened - Close or replace relief valve.
Transmission parts are defective or worn - Check and change faulty components.
Input drive shaft failure - Repair or replace drive shaft.
Air in the hydraulic system - Air bleeding is required.

Overheated drive system
Hydraulic oil level is low - Need to add oil.
Hydraulic fluid filter is clogged - Replace hydraulic filter.
Stuck relief valve - Repair or replace.
Hydraulic motor or drive pump failure - Check and repair if required.
Clogged hydraulic oil cooler - Clean the cooling fins.
Overloaded drive system - Load needs to be reduced.

Drive system is excessively noisy
Oil viscosity is incorrect - Use the specified type of oil.
Air in the hydraulic system - Need to bleed air.
Drive pump or hydraulic motor is damaged - Check and repair if required.
Worn or damaged mechanical parts of drive system - Inspect the parts for defect or damage and repair as required.

Hydraulics Troubleshooting

Hydraulic system is overheated
Hydraulic pressure incorrectly adjusted - Set pressure correctly.
Main relief valve malfunction or improper adjustment - Set up or change the relief valve.
Hydraulic fluid is dirty - Hydraulic fluid change required.
Lack of hydraulic oil - Add oil to the hydraulic system.
Hydraulic pump is faulty - Repair or change pump if required.

Lift arm won't raise or lower
Lift controls are faulty - Inspect and repair if necessary.
Hydraulic pump malfunction - Repair or install new hydraulic pump.
Hydraulic control valve failure - Replace or repair the valve.
Faulty hydraulic cylinder - Repair or change hydraulic cylinder.
Insufficient hydraulic fluid - Fill the system to proper hydraulic fluid level.

Bucket is not working
Faulty bucket tilt controls - Change or repair.
Hydraulic pump not working - Repair or install new hydraulic pump.
Hydraulic control valve malfunction - Change or repair hydraulic valve.
Faulty hydraulic bucket cylinder - Install a new cylinder or repair it.
Hydraulic fluid level low - Fill up the hydraulic fluid.

Boom or bucket is moving slowly
Hydraulic pump is faulty - Flow-rate pump and change pump if necessary.
Hydraulic cylinder oil leakage - Replace cylinder piston seals.
Low hydraulic fluid level - Fill the system to proper hydraulic fluid level.
Faulty or incorrect setting hydraulic control valve - Repair or set correctly.
Low hydraulic pressure - Correct adjustment is required.

Lift arm or bucket is working jerkily
Air in hydraulic system - Bleed hydraulic system.
Plugged hydraulic oil filter - Service or replace the hydraulic filter.
Hydraulic oil contamination - Fill up with fresh hydraulic oil.
Cylinder rod or tube is scratched - Change defective component.

Hydraulic pump makes excessive noise
Hydraulic leaks or lack of oil - Add hydraulic oil or correct system leaks.
Clogged hydraulic filter - Clean or replace the filter.
Suction line is dirty - Suction line must be serviced.
Air enters the pump - Air bleeding is required.
Damaged pump parts - Rebuild or change hydraulic pump.

Electrical Troubleshooting

Battery does not charge
Electrical wire connections are corroded or loose - Tighten or service connections.
Faulty battery terminal clamps - Install new terminal clamps.
Battery failing - Change the battery.
Worn or loose belt - Adjust belt tension or change the belt.

Starter turning slow
Low battery capacity - Battery is drained, charge it.
Battery is draining quickly - Battery needs service or replacement.
Terminals are faulty or battery cables are disconnected - Connect cables correctly or replace terminals.

Starter is not cranking
Battery is discharged or worn - Change or recharge battery.
Wiring is incorrectly connected or disconnected - Inspect wiring and connect correctly.
Low battery voltage - Charge the battery.
Faulty starter motor - Change or repair starter.