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| Home / Skid Steer Loaders / John Deere Skid Steer Loaders / John Deere 7775 |
John Deere 7775 Troubleshooting
The
John Deere 7775 skid steer loader driveline system components: a 137 cu.in
(2.2L) Yanmar 4TNE88 4-cylinder water-cooled diesel engine with a rated power of
49 hp (37 kW), and 1-speed hydrostatic transmission. The hydraulic system has a
pump with a rated capacity of 17 gal/min (64 l/min). The system pressure
is 2750 psi (190 bar). The John Deere 7775 is equipped with a vertical-lift
loader boom, heavy-duty drive chains, and 10x16.5 or 12x16.5 tires. The skid
steer loader has a max lift height of 115.5" (2935 mm) to hinge pin and dump
height of 90.4" (2295 mm). The rated operating capacity is 1705 lbs (775 kg),
and tipping load is 3410 lbs (1550 kg).
| Engine Troubleshooting |
Engine difficult to start or won't start
Air in fuel system - Bleed fuel system.
Fuel filter element clogging - Service the filter.
Faulty or dirty injection nozzles - Clean or replace injection nozzles.
Water or dirt in fuel system - Drain, flush, and service the system.
The valve clearance is incorrect - Adjustment procedure required.
Fuel injection pump is damaged - Change or repair the pump.
Engine starts but then stops
Dirty air cleaner - Clean or replace element.
Fuel filter plugged - Change filter element.
Fuel injection pump leakage - Check the fuel injection pump for leaks and fix it.
Damaged or clogged injectors - Inspect fuel injectors and change as required.
Fuel injection pump is not operating properly - Replace or repair injection pump.
Engine shuts off suddenly while running
Engine is not warmed up to the required temperature - Engine is not warmed up to the required temperature.
Fuel filter plugging - Install new filter element.
Air in fuel tank - Bleed fuel tank.
Clogged injection nozzle - Clean or replace injection nozzles.
Fuel injection pump timing is wrong - Use the correct fuel injection pump timing adjustment.
Engine stops at idle
Wrong adjustment of low idle speed - Need to adjust idle speed.
Fuel injection pump is damaged - Repair or install a new fuel pump.
Defective fuel injectors - Replace or clean fuel injectors.
Valve clearance is out of adjustment - Adjust valve clearance.
Engine power is insufficient
Plugged air cleaner - Clean or change cleaner.
Fuel injection nozzles are damaged or dirty - Install a new kit of correctly balanced nozzles.
Uneven fuel injection pressure - Test fuel injection pressure and adjust it correctly.
Valve clearance is not correct - Adjust to proper valve clearance.
Incorrectly set low idle speed - Need to adjust idle speed.
Fuel lines or hoses clogging - Clean fuel hoses and lines.
Cylinder head gasket is blown - Change cylinder head gasket.
Leaking or damaged piston rings - Piston rings need to be replaced.
Engine overheating
Coolant level is low - Fill radiator to proper level and check components for faults.
Engine oil level is low - Add oil to the engine crankcase.
Defective radiator cap or clogged radiator fins - Clean radiator or install new cap.
Loose or damaged fan belt - Belt replacement is recommended.
Diesel engine is overloaded - Reduce engine load.
Oil pressure is insufficient
Oil level is low - Checking oil level and add if necessary.
Oil filter is dirty - Service or change engine oil filter element.
Improper type of engine oil - Drain crankcase and refill with correct oil.
Excessive crankshaft bearing oil clearance - Bearing replacement required.
Defective oil pump - Check and replace if necessary.
Engine noises or knocks
Not enough engine oil - Fill up the engine oil.
Engine has not warmed up to the recommended temperature - Warm up the engine.
Timing of fuel injection pump is incorrect - Adjust fuel injection pump as required.
Improperly adjusted low idle speed - Test and adjust.
Fuel injectors are dirty or defective - Test and replace fuel injectors if necessary.
Connecting rod failure or misalignment - Alignment procedure or replacement is required.
Worn or scored pistons - Pistons replacement required.
| Drive System Troubleshooting |
Machine will not move in either direction or one direction
Hydraulic fluid level low - Add fluid as required.
Damaged drive chain - Inspect drive chain and replace defective parts.
Defective or worn relief valve - Relief valve need to be replaced or repair.
Suction line or hydraulic filter is dirty - Check, clean, or replace if required.
Defective or worn foot or hand controls - Change or repair.
Drive motor or pump is defective - Repair or change faulty component.
Reduced power
Plugged hydraulic oil filter - Replace hydraulic filter.
Open or damaged relief valve - Close or change relief valve.
Transmission components are defective or worn - Check and change faulty components.
Input drive shaft is damaged - Repair or replace faulty drive shaft.
There is air in the hydraulic system - Bleed air from system.
Drive system overheats
Low hydraulic fluid level - Fill up the hydraulic fluid.
Plugged hydraulic fluid filter - Check, clean, or replace as required.
Relief valve malfunction - Repair or replace.
Hydraulic motor or drive pump failure - Replace or repair faulty component.
Dirty oil cooler - Clean the cooling fins.
Drive system overload - Reduce drive system load.
Drive system is noisy
Oil viscosity is incorrect - Use oil of proper viscosity.
Hydraulic system is leaking air - Air bleeding is required.
Hydraulic motor or drive pump is worn - Inspect and replace as necessary.
Mechanical parts of drive system are damaged or worn - Inspect drive system and replace faulty parts.
| Hydraulics Troubleshooting |
Hydraulic system overheated
Hydraulic pressure is not correct - Adjust pressure correctly.
Main relief valve failure or improper setting - Adjust relief valve or change if required.
Hydraulic fluid contamination - Change hydraulic fluid.
Lack of hydraulic fluid - Check and refill the hydraulic fluid.
Worn hydraulic oil pump - Replace or repair pump if necessary.
Lift arm can't drop or lift
Faulty lift controls - Repair or replace.
Damaged hydraulic oil pump - Replace or repair pump if necessary.
Hydraulic control valve malfunction - Install a new valve or repair it.
Defective hydraulic cylinder - Repair or replace hydraulic cylinder.
Hydraulic fluid is insufficient - Add fluid as required.
Bucket does not tilt
Damaged bucket controls - Repair or replace.
Hydraulic pump malfunction - Repair or change pump if required.
Hydraulic control valve is defective - Change or repair hydraulic valve.
Broken bucket cylinder - Replace or repair cylinder.
Hydraulic fluid is insufficient - Add fluid as required.
Boom or bucket functions slowly
Hydraulic pump is defective - Check pump capacity and change if necessary.
Oil leaks from hydraulic cylinder - Change cylinder piston seals.
Insufficient hydraulic oil - Need to add oil.
Faulty or incorrect setting hydraulic control valve - Repair or adjust properly.
Low hydraulic pressure - Adjust it correctly.
Lift arm or bucket is moving jerkily
Air trapped in hydraulic system - Bleed air from system.
Hydraulic oil filter is dirty - Change or clean oil filter.
Dirty hydraulic oil - The oil must be changed.
Cylinder rod or tube is scuffed - Change defective component.
Hydraulic pump is noisy
Lack of oil or hydraulic leakage - Repair hydraulic leaks or add oil as required.
Hydraulic filter is clogged - Clean or install new filter.
Clogged suction line - Suction line must be serviced.
Pump sucks air - Air bleeding is required.
Pump components are worn out - Rebuild or change hydraulic pump.
| Electrical Troubleshooting |
Battery will not charge
Electrical cable connections are loose or corroded - Clean or tighten connections.
Battery terminal connectors are faulty - Replace terminal connectors.
Battery is worn - Install a new battery.
Belt is damaged or loose - Replace belt or adjust belt tension.
Starter cranks slowly
Low battery voltage - Low battery charging, charge as required.
Battery drains quickly - Battery needs service or replacement.
Terminals are faulty or battery cables are disconnected - Connect cables correctly or replace terminals.
Starter will not crank
Battery is low or faulty - Need to charge or replace the battery.
Wire harness is disconnected or incorrectly connected - Check wire harness and connect as required.
Low battery capacity - Battery needs to be recharged.
Damaged starter motor - Repair or replace starter.
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| SKID STEER LOADERS SPECIFICATIONS |