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Ford 7700 Tractor Troubleshooting

The Ford 7700 row-crop tractor was manufactured between 1975 and 1981. The Ford 7700 is powered by Ford 256 4-cycle four-cylinder liquid-cooled diesel engine with a maximum power of 96.7 Hp (72.1 kilowatt) and 369 Nm (272 lb-ft) of peak torque at 1600 rpm.

The Ford 7700 tractor is equipped with two types of transmission. 1st type: 16x4 Dual-Power transmission. 2nd type: 8x2 Dual-Range gear transmission. The max. forward speed - 18.6 mph (30 km/h), a max. reverse speed - 9 mph (14.5 km/h).

The open center hydraulic system used a gear pump with flow rate of 9.7 gpm (36.9 lpm). The hydraulic system pressure is 172.5 bar (2500 psi). The Ford 7700 is fitted with 7.50x18 front tires and 18.4x34 rear tires. The wheelbase is 101.6 in (2580 mm). The tractor is compatible with two front end loader models. The Ford 774 loader has a lift capacity to full height of 2000 lbs (907 kg). The Ford 772QT loader has a lift capacity to max height of 2500 lbs (1134 kg).

Engine Troubleshooting
Engine will not start or hard to start
Fuel filter plugging - Install new filter element
Fuel supply valve is closed - Open fuel supply valve
Fuel-line is leaking air - Retighten clamps, replace defective pipes
Fuel injectors are damaged or dirty - Service or change fuel injectors
Fuel injection pump is broken - Rebuild or replace pump
Poor cylinder compression - Inspect cylinder block and change worn parts
Engine stops running unexpectedly
Engine is not fully warmed up - Warm up engine as required
Fuel-line is leaking air - Retighten clamps, replace defective pipes
Irregular fuel injection - Adjust fuel injection timing
Fuel filter plugging - Service the filter
Fuel injectors are damaged or dirty - Service or change fuel injectors
Diesel starts but then stalls
Timing of fuel injection pump is not adjusted - Check the fuel injection pump timing setting
Dirty fuel filter element - Change filter element
Clogged or damaged injector nozzles - Install a new set of well-balanced nozzles
Damaged fuel injection pump - Repair or install a new fuel pump
Air cleaner element clogging - Replace cleaner or install new cleaner element
Engine stops while idling
Low idle speed adjustment is incorrect - Adjustment required
Fuel injection pump failure - Install a new pump or rebuild
Fuel injector nozzles are dirty or defective - Test injector nozzles and replace as required
Incorrect valve clearance - Correct valve clearance
Engine overheating
Coolant level is low - Refill to the correct level. Check system for leaks
Cooling system parts are damaged or system is dirty - Replace faulty parts or flush the cooling system
Engine oil level is low - Check oil level and add oil as required
Worn fan belt or incorrect belt tension - Adjust belt tension properly or change it
Defective or wrong type of thermostat - Check and replace if required
Engine lacks power
Fuel injectors are clogged or faulty - Change fuel injectors
Incorrect fuel injection pressure - Check the fuel injection pressure and adjust if necessary
Clogged air filter element - Replace filter or install new filter element
Oil filter clogging - Service or replace engine oil filter
Engine overloaded - Load reducing is recommended
The valve clearance is incorrect - Adjust to proper valve clearance
Incorrectly adjusted low idle speed - Adjust low idle speed
Restricted fuel hoses or pipes - Fuel pipes and hoses need to be cleaned
Engine compression too low: Valves are faulty or leaking - Have valves replaced
Engine noise or knocking
Timing of fuel injection pump is not adjusted - Correct injection timing
Fuel injector nozzles are damaged - Replace fuel injector nozzles
Engine oil insufficient - Add oil to the engine crankcase
Engine is cold - Warm up engine to required temperature
Crankshaft or main bearings failure - Crankshaft or bearings need to be replaced
Damaged or defective piston rings - Piston rings replacement required
Loose flywheel bolts - Inspect flywheel bolts and tighten properly
High engine oil consumption
External oil leaks: Gaskets or seals are excessively worn - Replace worn parts to avoid leaks
Improper oil viscosity - Use proper viscosity oil
Piston rings are defective or worn - Have piston rings replaced
Valve guides and stems are worn - Valves must be replaced
Cylinder liners or pistons are damaged - Inspect pistons and liners, change as required

Electrical System Troubleshooting
Battery is not charging
Faulty cell in battery - Change the battery
Battery electrical wire harness damage - Check battery wires for damage, replace or change
Battery cables and terminals are corroded or loose - Cables and terminals must be tightened or cleaned
Damaged belt or incorrectly adjusted belt tension - Install new belt or adjust belt tension as required
Starter turns slowly
Low battery capacity - Charge the battery
Battery does not hold charge - Service or replace the battery
Battery wiring harness failure - Inspect electrical cables for defects, repair or replace
Loose or corroded battery terminals and cables - Tighten or service cables and terminals
Starter will not crank
Low battery output voltage - Recharge the battery
Drained or faulty battery - Replace or charge as required
Starter motor failing - Starter should be replaced
Incorrectly connected or disconnected wires - Check battery wires and connect correctly

Transmission Troubleshooting
Hard shifts
Failure or improper clutch adjustment - Adjust or replace the clutch
Gear shift linkage is damaged or loose - Service or replace shift linkage
Bent or worn shift forks - Shift forks need to be changed
Faulty gear shifting mechanism - Faulty parts must be changed
Insufficient transmission oil pressure
Low transmission oil level - Fill up the transmission oil
Transmission fluid filter is plugged (if fitted) - Change or service the transmission fluid filter
Damaged relief valve - Install a new relief valve
Transmission makes excessive noise
Bearings are worn or broken - Replace the bearings
Low transmission oil level - Correct the transmission oil level
Transmission fluid contamination - Change transmission fluid
Incorrect backlash or gears are defective - Change worn gears or set backlash correctly
Bent or worn shift forks - Shift forks need to be changed
Transmission fluid leaks
Broken gaskets or seals - Seals and gaskets need to be replaced
Cracked transmission case - Install a new transmission case

Hydraulics Troubleshooting
Excessive hydraulic system heat
Improper hydraulic system pressure setting - Set the pressure properly
Main relief valve is faulty or misadjusted - Adjust or change relief valve
Dirty hydraulic oil - The oil must be changed
Air enters in hydraulic system - Check the pump seals, suction line, and fittings
Low hydraulic oil pressure
Hydraulic oil level is low - Add oil to the hydraulic system
Hydraulic fluid filter element is dirty - Clean the hydraulic filter or install new filter element
Hydraulic pump is defective - Test pump flow rate and replace pump if required
Hydraulic control valve block is defective or set improper - Set correctly or replace
Hydraulic cylinder malfunction - Check the hydraulic cylinder parts for damage or wear and replace if necessary
Hydraulic pipes are leaking - Find leaks in the system and fix it
3-point hitch does not raise or raises very slowly
Hydraulic oil level is low - Fill the hydraulic system with oil
Hydraulic fluid is too cold - Allow fluid to warm
Hydraulic oil filter clogging - Change the hydraulic filter element or service if required
Hydraulic pump failure - Check the pump capacity and replace pump if required
Main relief valve is damaged or adjusted improperly - Replace or set up the relief valve
Hydraulic control valve is faulty or out of adjustment - Replace or adjust properly
Hydraulic cylinder is faulty - Inspect cylinder components for wear or damage and change if required
Disconnected or damaged suction pipe - Connect or replace
Three-point hitch dropping is too slow or cannot be dropped
Defective or incorrect setting hydraulic control valve block - Adjust correctly or replace
Hydraulic cylinder is faulty - Check cylinder parts for wear or damage and replace if necessary
Worn hitch rock shaft - Install a new shaft
Hitch has mechanical defects - Replace defective or worn hitch components
Hitch lowering or lifting is not smoothly
Hydraulic system sucks air - Inspect the suction line, pump seals, and fittings
Hydraulic oil contamination - Change the oil
Hydraulic pump malfunction - Flow-rate hydraulic pump and replace pump if necessary
Faulty or incorrect setting hydraulic spool valve - Replace or adjust properly
Broken hydraulic cylinder - Check the hydraulic cylinder parts for damage or wear and replace if necessary

Steering System Troubleshooting
Difficult steering
Steering column is damaged or incorrectly assembled - Steering column must be assembled correctly or changed
Air trapped in the steering system - Bleed the system of air
Clogged steering filter - Install new steering filter element
Improper toe-in - Adjust toe-in wheels properly
Front tires are worn out - Install new tires
Faulty steering pump - Steering pump needs to be repaired or replaced
Power steering control valve is damaged or worn - Repair or change the steering control valve
Relief valve seizing or malfunction - Flush relief valve or change if necessary
Low steering fluid level - Fill the steering system with fluid
Steering system has oil leaks - Tighten the steering line and hose joints
Excessive steering wheel play
Steering column coupling or shaft is worn - Change defective part
Power steering control valve is worn or defective - Check and replace as required
Faulty or worn steering unit - Replace or repair steering unit as required
Steering pump is faulty - Install a new steering pump
Steering tie-rod ends or linkage are worn - Replace damaged part
Front wheels wander to left or right
Incorrect tire pressure - Inflate the tires correctly
Not adjusted toe-in - Adjust toe-in correctly
Worn or faulty steering tie-rod ends or linkage - Replace failed part
Faulty or worn power steering control valve - Replace or repair steering control valve as required
Steering cylinder is worn - Replace or repair hydraulic steering cylinder
Incorrectly adjusted or damaged front hub bearings - Replace or adjust the bearings correctly




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MF 250 MF 690 MF 3060 MF 6180
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