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Ford 7840 Tractor Troubleshooting
The
Ford 7840 is a PowerStar 40-series row-crop tractor. This model was manufactured
between 1991 and 1995. The Ford 7840 tractor is powered by 401 cu.in (6.6 L)
Ford Genesis four stroke six-cylinder liquid-cooled diesel engine with operating
power of 100 hp (73.5 kW) at 2100 rev/min.
The Ford 7840 was fitted with 4 types of transmission. Type 1: 8x2
EconoShift constant mesh transmission. Type 2: 16x4 Dual Power
transmission with a 2-speed powershift. Type 3: 12x12 Synchro Shift
synchronized transmission. Type 4: 16x16 Pulse Command transmission with
a 4-speed powershift.
Max. forward speed - 19.2 mph (30.9 kph), maximum reverse speed - 19.1
mph (30.7 kph). The open center hydraulic system includes a gear pump
with rated capacity of 9.3 gpm (35.2 lpm). The hydraulic pressure is 182
bar (2650 psi). The Ford 7840 was equipped with 10.0x16 front tires and
18.4x30 rear tires. The wheelbase is 106.3" (2700 mm) for 2WD models, or
103.3" (2623 mm) for 4WD models.
| Engine Troubleshooting |
| Engine won't start or hard to start |
| Fuel filter is clogged - Change the filter element |
| No fuel injection - Open fuel cock to inject fuel |
| Air in fuel pipes - Bleed fuel pipes |
| Clogged or damaged injectors - Clean or replace fuel injectors |
| Fuel injection pump malfunction - Replace or rebuild injection pump |
| Poor engine compression - Inspect cylinder block and replace worn components |
| Engine stalls during operation |
| Low coolant temperature - Warm up engine to required temperature |
| Fuel lines leaking air - Tighten clamps, change faulty pipes |
| Improper fuel injection - Fuel injection settings required |
| Fuel filter is clogged - Service or replace the filter |
| Clogged or damaged injectors - Inspect fuel injectors and replace if necessary |
| Diesel starts and then stalls |
| Fuel injection pump out of timing - Fuel injection pump timing adjustment needs to be corrected |
| Clogged fuel filter element - Filter maintenance required |
| Fuel injector nozzles are damaged - Install new set of properly balanced nozzles |
| Fuel injection pump damage - Replace or rebuild injection pump |
| Air cleaner is clogged - Change or replace air cleaner element |
| Low idle speed set incorrectly - Adjust as required |
| Fuel injection pump malfunctioning - Change or repair the pump |
| Fuel injector nozzles are defective or dirty - Inspect injector nozzles and change if required |
| Excessive valve clearance - Check and adjust |
| Not enough coolant - Fill cooling system to proper level. Check for leaks or other malfunctions |
| Cooling system is dirty or cooling components are failed - Flush cooling system or replace faulty parts |
| Lack of engine oil - Check and refill engine oil |
| Broken fan belt or improper belt tension - Adjust belt tension properly or replace it |
| Thermostat failure - Replace the thermostat |
| Diesel engine is losing power |
| Dirty or damaged injectors - Check fuel injectors and replace if required |
| Incorrect fuel injection pressure - Adjust pressure to proper level |
| Air filter element is dirty - Install new filter element or replace it |
| Oil filter is clogged - Clean or change engine oil filter |
| Engine is under excessive load - Change to lower gear or reduce load |
| Valve clearance is wrong - Have it adjusted |
| Incorrect low idle setting - Normalize low idle speed |
| Fuel hoses or pipes clogging - Clean fuel pipes and hoses |
| Engine compression is insufficient: Valves are defective or worn - Valves need to be replaced |
| Engine knocking sound or abnormal noise |
| Unadjusted fuel injection pump timing - Check the fuel injection pump timing setting |
| Damaged or clogged injector nozzles - Test injector nozzles and replace as required |
| Engine oil insufficient - Fill the crankcase with engine oil |
| Engine is not preheated - Warm up the engine |
| Main bearings or crankshaft failure - Have bearings or crankshaft replaced |
| Stuck or worn piston rings - Have piston rings replaced |
| Loose flywheel bolts - Inspect flywheel bolts and tighten properly |
| Diesel engine using too much oil |
| Oil leakage: Gaskets or seals may be damaged - New components need to be installed |
| Crankcase oil too light - Use oil of correct viscosity |
| Stuck or worn piston rings - Install new piston rings |
| Valve stems or guides are damaged - Replace defective valves |
| Cylinder liners or pistons are worn - Inspect pistons and liners, change as required |
| Electrical System Troubleshooting |
| Battery will not charge |
| Battery failing - Install a new battery |
| Bad battery wiring harness - Inspect wiring for malfunctions, replace or repair |
| Loose or corroded battery cables and terminals - Service or tighten battery terminals and cables |
| Belt is damaged or belt tension is incorrectly adjusted - Replace belt or adjust belt tension correctly |
| Battery capacity is low - Battery is drained, recharge it |
| Battery drains quickly - Service charging system or change battery |
| Damaged battery cable harness - Check electrical cables for damage, repair or replace |
| Corroded or loose battery terminals and cables - Terminals and cables need to be tightened or cleaned |
| Low battery capacity - Battery needs to be recharged |
| Discharged or worn battery - Battery needs to be recharged or replaced |
| Starter motor is damaged - Repair or replace starter |
| Battery cables are disconnected or incorrectly connected - Check cables and reconnect it correctly |
| Transmission Troubleshooting |
| Gear hard to shift |
| Worn or misadjusted clutch - Clutch needs to be replaced or adjusted |
| Gear shift linkage is stuck or worn - Service or change the shift linkage |
| Damaged or worn shift forks - Change defective shift forks |
| Faulty parts in the gear shifting mechanism - Change faulty parts |
| Transmission oil pressure is insufficient |
| Low transmission fluid level - Check transmission fluid level and add it as required |
| Dirty transmission oil filter (if fitted) - Change or service the transmission oil filter |
| Relief valve is defective - Change relief valve |
| Transmission is making noise |
| Bearings are worn or broken - Bearings need to be changed |
| Lack of transmission fluid supply - Fill the transmission housing with fluid |
| Contaminated transmission fluid - Fill up with fresh transmission fluid |
| Incorrect backlash or gears are defective - Replace gears or adjust backlash properly |
| Worn or damaged shift forks - Shift forks need to be replaced |
| Transmission fluid leakage |
| Gaskets or seals are defective Gaskets or seal replacement required |
| Cracked transmission housing - Housing needs to be replaced |
| Hydraulics Troubleshooting |
| Hydraulic system overheated |
| System pressure has not been adjusted correctly - Pressure needs to be adjust correctly |
| Main relief valve is defective or unadjusted - Set up or change the relief valve |
| Hydraulic fluid contamination - Change hydraulic fluid |
| Aeration in hydraulic system - Inspect the pump seals, suction line, and fittings |
| Hydraulic fluid pressure too low |
| Lack of hydraulic oil - Fill up the hydraulic oil |
| Hydraulic oil filter is dirty - Clean the hydraulic filter element or replace if necessary |
| Hydraulic pump is faulty - Check pump capacity and change if necessary |
| Hydraulic control valve is defective or set improper - Change or adjust correctly |
| Hydraulic cylinder is broken - Check the hydraulic cylinder components for damage or wear and change if necessary |
| Leakage in hydraulic pipes - Find leaks in hydraulic system and repair it |
| 3-point hitch won't raise or raises slowly |
| Not enough hydraulic fluid in the system - Fill the hydraulic system with oil |
| Cold fluid in hydraulic system - Wait for fluid to warm up |
| Hydraulic fluid filter is clogged - Replace hydraulic filter element or service if necessary |
| Hydraulic pump malfunction - Check pump flow and change pump if necessary |
| Main relief valve is defective or unadjusted - Adjust or replace the relief valve |
| Defective or incorrect setting hydraulic spool valve block - Change or adjust properly |
| Hydraulic cylinder is not working - Check the hydraulic cylinder components for damage or wear and change if necessary |
| Suction pipe is damaged or loose - Repair or change |
| 3-point hitch lowers slowly or won't lower |
| Hydraulic spool valve block is faulty or out of adjustment - Set correctly or replace |
| Hydraulic cylinder malfunction - Check cylinder parts for wear or damage and replace if necessary |
| Hitch cross shaft is worn - Replace the shaft |
| Internal mechanical malfunction with hitch - Change damaged or worn hitch parts |
| Hitch is lowered or raised jerkily |
| Air in hydraulic system - Check the suction line, pump seals, and fittings |
| Hydraulic oil is contaminated - Fill up with fresh hydraulic oil |
| Hydraulic pump not working - Test pump flow rate and replace pump if required |
| Hydraulic control valve is not set properly or defective - Replace or adjust correctly |
| Hydraulic cylinder failure - Inspect cylinder parts for wear or damage and replace if required |
| Steering System Troubleshooting |
| Hard Steering |
| Steering column is defective or improperly assembled - Change steering column or assemble properly |
| Air enters in steering system - Air-bleed steering system |
| Dirty steering filter - Change steering filter element |
| Incorrect toe-in adjustment - Check toe-in and correct |
| Low tire pressure - Inflate the tires |
| Hydraulic steering pump is defective - Repair or change steering pump |
| Defective or worn power steering control unit - Replace or repair steering unit as required |
| Relief valve sticking or malfunction - Install a new relief valve or clean it |
| Lack of steering oil - Fill the steering system with oil |
| Steering system oil leakage - Retighten steering hose and pipe connections |
| Steering wheel free play is excessive |
| Worn steering column coupling or shaft - Change faulty part |
| Damaged or worn power steering control unit - Inspect and change as required |
| Faulty steering cylinder - Repair or change steering cylinder |
| Steering pump not working - Check the steering pump and replace if necessary |
| Steering tie-rod ends or linkage are worn - Replace damaged component |
| Front wheels wander to right or left |
| Tire pressure is not correct - Check tire pressure and inflate as required |
| Toe-in adjustment is incorrect - Check toe-in and correct |
| Steering tie-rod ends or linkage are defective - Replace damaged component |
| Power steering control unit is defective or worn - Check and replace as required |
| Faulty steering cylinder - Repair or change steering cylinder |
| Front hub bearings are damaged or incorrectly adjusted - Replace the bearings or adjust it properly |
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| Farm Tractors Technical Specifications |
