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John Deere 4840 Troubleshooting
The
John Deere 4840 is a two-wheel drive row-crop tractor from Iron Horses series.
This model was manufactured between 1978 and 1982. The JD 4840 driveline
components: John Deere 6466 four-stroke six-cylinder direct injection
turbocharged intercooled diesel engine and 8x4 full powershift transmission.
A 466 cubic inches (7.6 L) engine has a cylinder bore of 4.56" (116 mm),
piston stroke of 4.75" (121 mm), and rated power of 200 hp (148.1 kW).
The maximum travel speed (forward and reverse): 18.6 mph (29.9 km/h) /
6.4 mph (10.3 km/h).
The closed center hydraulic system used a pump with a flow of 23 gpm
(87.1 lpm) gpm. The hydraulic pressure is 157 bar (2275 psi). The John
Deere 4840 was equipped with a power steering system, differential
hydraulic wet disc brakes, 11.00x16 or 16.5Lx16.1 front tires, and
18.4x38 or 18.4x42 rear tires. The wheelbase is 118.5 inches (3000 mm).
| Engine Troubleshooting |
| Engine hard starting or not starting |
| Plugged fuel filter - Clean or change the filter |
| Closed fuel supply valve - Open supply valve to inject fuel |
| There is air in the fuel system - Bleed the system |
| Fuel injectors are clogged or faulty - Test fuel injectors and change if necessary |
| Fuel injection pump failure - Install a new pump or rebuild |
| Bad cylinder compression - Inspect cylinder block and replace worn components |
| Engine stops running unexpectedly |
| Low coolant temperature - Warm up engine as required |
| There is air in the fuel system - Bleed the system |
| Bad fuel injection - Check and adjust |
| Fuel filter plugging - Change filter element |
| Fuel injectors are damaged or dirty - Clean or replace fuel injectors |
| Engine starts but immediately shuts off |
| Fuel injection pump out of timing - Correct injection timing |
| Dirty fuel filter element - Service or replace the filter |
| Faulty fuel injector nozzles - Service or replace injector nozzles |
| Fuel injection pump is not working correctly - Install a new fuel pump or repair |
| Dirty air cleaner element - Replace or service air cleaner element |
| Wrong adjustment of low idle speed - Test and adjust |
| Fuel injection pump is defective - Rebuild or replace pump |
| Fuel injector nozzles fault - Service or replace injector nozzles |
| Valve clearance is not correct - Have it adjusted |
| Insufficient coolant fluid - Top up coolant fluid. Check the components of cooling system |
| Cooling system parts are defective or system is dirty - Replace faulty parts or service cooling system |
| Lack of engine oil - Fill the crankcase with engine oil |
| Broken fan belt or incorrect belt tension - Replace or adjust belt tension properly |
| Defective thermostat - Test thermostat opening temperature, replace as required |
| Clogged or damaged injectors - Change fuel injectors |
| Incorrect fuel injection pressure - Repair or replace injection pump |
| Clogged air filter - Clean or replace the air filter element |
| Clogged oil filter - Change or clean engine oil filter element |
| Engine is overloaded - Load reducing required |
| Excessive valve clearance - Correct valve clearance |
| Incorrect low idle setting - Adjustment required |
| Fuel pipes or hoses are dirty - Clean fuel pipes and hoses |
| Engine losing compression: Valves are broken or leaking - Have valves replaced |
| Timing of fuel injection pump is not adjusted - Check and correct adjustments |
| Fuel injector nozzles are damaged or dirty - Change or clean injector nozzles |
| Engine oil level is low - Fill up the oil to required level |
| Engine has not warmed up to the recommended temperature - Warm up to required temperature |
| Main bearings or crankshaft are worn out - Have bearings or crankshaft replaced |
| Piston rings are damaged or broken - Have piston rings replaced |
| Flywheel mounting screws are loose - Tighten the screws |
| Diesel engine using too much oil |
| Oil leaking: Worn seals or gaskets - To repair leaks, replace worn parts |
| Crankcase oil too light - Use oil of correct viscosity |
| Stuck or defective piston rings - Piston rings replacement required |
| Damaged valve stems or valve guides - Valves must be replaced |
| Damaged cylinder liners or pistons - Inspect pistons and liners, replace as required |
| Electrical System Troubleshooting |
| Battery cannot be charged |
| Worn-out battery - Install a new battery |
| Damaged battery electrical wire harness - Inspect electrical wires for damage, change or repair |
| Loose or corroded battery cables and terminals - Tighten or clean terminals and cables |
| Defective belt or improperly adjusted belt tension - Adjust belt tension properly or replace belt |
| Battery capacity is low - Battery is drained, recharge it |
| Battery discharges quickly - Service or replace the battery |
| Damaged battery cable harness - Check electrical cables for damage, repair or replace |
| Loose or corroded cables and terminals - Tighten or service cables and terminals |
| Battery voltage is low - Low battery charging, charge as required |
| Drained or worn battery - Need to charge or replace the battery |
| Starter motor failing - Starter needs to be replaced |
| Wiring is improperly connected or disconnected - Need to reconnect the wiring properly |
| Transmission Troubleshooting |
| Hard shifts |
| Clutch is unadjusted or worn - Replace or adjust clutch |
| Damaged or loose gear shift linkage - Service or replace shift linkage |
| Worn or damaged shift forks - Replace defective shift forks |
| Gearshift mechanism is worn out - Repair or replace worn components if required |
| Low transmission oil pressure |
| Not enough fluid in transmission - Fill system with correct transmission fluid level |
| Dirty transmission oil filter (if fitted) - Replace or service transmission oil filter |
| Relief valve sticking - Replace valve as required |
| Transmission is making noise |
| Bearings are worn or damaged - Bearings replacement required |
| Lack of transmission fluid supply - Check and refill the transmission fluid |
| Dirty transmission fluid - Fill up with fresh transmission fluid |
| Gears are defective or backlash is incorrect - Change the gears or adjust backlash correctly |
| Bent or worn shift forks - Replace defective shift forks |
| Broken gaskets or seals - Seals and gaskets replacement required |
| Cracked transmission housing - Housing needs to be replaced |
| Hydraulics Troubleshooting |
| Hydraulic system overheating |
| Hydraulic system pressure is unadjusted - Adjust the pressure as required |
| Faulty or incorrectly adjusted main relief valve - Adjust or replace the relief valve |
| Contaminated hydraulic fluid - Change hydraulic fluid |
| Air leaks in hydraulic system - Inspect the suction line, pump seals, and fittings |
| Hydraulic fluid pressure is low |
| Lack of hydraulic fluid - Need to add fluid |
| Hydraulic oil filter element clogging - Replace hydraulic filter element or service if necessary |
| Hydraulic pump is faulty - Check the pump capacity and replace pump if required |
| Damaged or incorrect adjusted hydraulic control valve - Change or set correctly |
| Defective hydraulic cylinder - Inspect cylinder components for wear or damage and change if required |
| Hydraulic lines are leaking - Find leaks in hydraulic system and repair it |
| 3-point hitch does not raise or raises very slowly |
| Not enough hydraulic fluid in the system - Check and refill the hydraulic fluid |
| Cold hydraulic fluid - Warm up the fluid |
| Hydraulic oil filter clogging - Hydraulic filter maintenance required |
| Defective hydraulic pump - Test the pump performance and change pump if required |
| Main relief valve incorrect adjustment or failure - Adjust the valve or replace if necessary |
| Hydraulic spool valve is not set properly or defective - Replace or adjust properly |
| Hydraulic cylinder is faulty - Inspect the hydraulic cylinder parts for damage or wear and replace if required |
| Loose or damaged suction line - Tighten or replace |
| Hitch not dropping or hitch drops slowly |
| Faulty or incorrect setting hydraulic control valve - Replace or adjust properly |
| Defective hydraulic cylinder - Check the hydraulic cylinder parts for damage or wear and replace if necessary |
| Hitch cross shaft is damaged - Replace the shaft |
| Hitch has mechanical defects - Change defective or worn hitch parts |
| Hitch raises or lowers not smoothly |
| Air leaks in hydraulic system - Inspect the pump seals, suction pipe, and fittings |
| Dirty hydraulic fluid - The fluid must be changed |
| Hydraulic pump not working - Check hydraulic pump flow and replace pump if necessary |
| Hydraulic spool valve is not set properly or defective - Set correctly or replace |
| Hydraulic cylinder is faulty - Inspect the hydraulic cylinder parts for damage or wear and replace if required |
| Steering System Troubleshooting |
| Steering wheel is difficult to turn |
| Steering column is defective or improperly assembled - Change steering column or assemble properly |
| Air enters in steering system - Bleed air from system |
| Improper toe-in adjustment - Check toe-in and correct |
| Incorrect tire pressure - Inflate the tires correctly |
| Faulty steering pump - Repair or change steering pump |
| Worn or defective steering valve assembly - Check and replace as required |
| Stuck or worn relief valve - Flush relief valve or change if necessary |
| Steering fluid level is low - Check fluid level and add steering fluid as required |
| Steering system oil leakage - Tighten joints of hydraulic pipes and hoses in steering system |
| Excessive steering wheel free play |
| Steering column shaft or coupling is worn out - Change defective part |
| Steering valve assembly is worn or defective - Inspect and replace as required |
| Defective hydraulic steering pump - Install a new steering pump |
| Worn or faulty steering linkage or tie-rod ends - Change damaged part |
| Tractor is pulling to left or right |
| Deflated front tyres - Inflate tyres as needed |
| Toe-in adjustment is incorrect - Check and adjust toe-in |
| Steering tie-rod ends or linkage are defective - Replace failed part |
| Steering valve assembly is defective or worn - Replace or repair steering valve as required |
| Incorrectly adjusted or damaged front hub bearings - Adjust properly or replace bearings |
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| Farm Tractors Technical Specifications |
