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Kubota L3750 Troubleshooting
The
Kubota L3750 L-series compact utility tractor was manufactured from 1984 to
1990. The tractor was designed in 2 versions: L3750F (2WD) and L3750DT (4WD).
The Kubota L3750 powerline system components: Kubota F2302-DI 5-cylinder
direct injection water-cooled naturally aspirated diesel engine and
partially synchronized transmission with 8 forward and 8 reverse gears.
A 141.9 cubic inches (2.3L) engine has a cylinder bore of 3.35" (85 mm),
piston stroke of 3.23" (82 mm), and rated power of 45 hp (33.6 kW).
The maximum travel speed (forward/reverse): 14.2 mph (22.8 km/h). The
open center hydraulic system used a gear pump with rated capacity of 8.7
gal/min(32.9 l/min). The hydraulic system pressure is 172.5 bar (2500
psi). The 2-wheel drive models are equipped with 6.50x16 front tyres and
13.6x28 rear tyres. The 9.50x16 front tyres and 13.6x28 rear tyres fit
4-wheel drive tractors. The wheelbase is 76.4" (1940 mm).
Compatible attachments for the Kubota L3750 tractor: Kubota BF900 loader
with lift capacity to full height of 1985 lbs (900 kg), and Kubota L4540
backhoe with maximum digging depth of 123" (3120 mm) and bucket digging
force of 3980 lbs (1805 kg).
| Engine Troubleshooting |
| Diesel won't start or hard to start |
| Fuel filter is clogged - Service or replace the filter |
| Fuel is not supplied from the tank to the system - Check the fuel shut-off valve |
| Fuel-line is leaking air - Retighten clamps, replace defective pipes |
| Fuel injectors are damaged or dirty - Change fuel injectors |
| Fuel injection pump malfunction - Repair or install a new fuel pump |
| Low engine compression - Check and replace worn parts |
| Engine stalls during operation |
| Engine is not fully warmed up - Warm up the engine as required |
| Air in fuel pipes - Bleed fuel pipes |
| Irregular fuel injection - Adjust fuel injection timing |
| Dirty fuel filter element - Service or replace the filter |
| Fuel injectors are defective or dirty - Service or change fuel injectors |
| Diesel engine stalls after starting |
| Fuel injection pump timing is incorrect - Correct injection timing |
| Fuel filter clogging - Clean the filter element |
| Clogged or damaged injector nozzles - Service or replace injector nozzles |
| Faulty fuel injection pump - Replace or repair injection pump |
| Dirty air cleaner - Replace or service air cleaner element |
| Engine shuts off while idling |
| Low idle speed setting is not correct - Adjust low idle speed |
| Fuel injection pump malfunction - Change or repair the pump |
| Fuel injector nozzles are damaged or dirty - Service or replace injector nozzles |
| Excessive valve clearance - Correct valve clearance needs to be set |
| Low engine coolant - Top up coolant fluid. Check and repair damage to the cooling system if required |
| Cooling system is dirty or cooling components are failed - Replace faulty parts or flush the cooling system |
| Engine oil level low - Fill up the engine oil |
| Fan belt is defective or belt tension is not adjusted - Adjust belt tension properly or change it |
| Thermostat failure - Check and replace if required |
| Fuel injectors are defective or dirty - Inspect fuel injectors and replace if necessary |
| Fuel injection pressure is incorrect - Test fuel injection pressure and adjust it correctly |
| Air filter element is clogged - Install new filter element or replace it |
| Dirty oil filter - Clean or replace engine oil filter element |
| Engine is under excessive load - Load reducing is recommended |
| Incorrect valve clearance - Adjust to proper valve clearance |
| Low idle speed setting is incorrect - Adjust low idle speed |
| Clogged fuel pipes or hoses - Fuel hoses and pipes must be clean |
| Insufficient engine compression: Leaking or faulty valves - Replace the valves |
| Incorrectly set fuel injection pump timing - Fuel injection pump timing adjustment needs to be corrected |
| Dirty or defective injector nozzles - Inspect injector nozzles and change if required |
| Insufficient engine oil - Fill up the engine oil |
| Engine not warmed up - Normalize the temperature by warming up the engine |
| Main bearings or crankshaft are worn out - Replace crankshaft or bearings |
| Piston rings are damaged or broken - Piston rings replacement required |
| Flywheel screws are loose - Tighten the screws firmly |
| Diesel engine using too much oil |
| External oil leaks: Gaskets or seals may be damaged - Defective components must be replaced |
| Wrong oil viscosity - Fill up with the proper oil viscosity |
| Worn or stuck piston rings - Install new piston rings |
| Worn valve stems and valve guides - Valves replacement required |
| Scored pistons or cylinder liners - Inspect pistons and liners, replace as required |
| Electrical System Troubleshooting |
| Battery will not charge |
| Faulty cell in battery - Battery replacement required |
| Battery cable harness damage - Check battery cables for damage, change or repair |
| Loose or corroded battery cables and terminals - Tighten or clean terminals and cables |
| Belt damage or incorrect belt tension adjustment - Replace belt or correctly adjust belt tension |
| Low battery power - Battery is drained, recharge it |
| Battery discharges quickly - Battery needs service or replacement |
| Bad battery wiring harness - Inspect wiring for malfunctions, replace or repair |
| Loose or corroded battery cables and terminals - Clean or tighten terminals and cables |
| Low battery capacity - Battery is drained, charge it |
| Drained or defective battery - Change or recharge battery |
| Starter motor failing - Starter should be changed |
| Wiring is improperly connected or disconnected - Need to reconnect the wiring properly |
| Transmission Troubleshooting |
| Difficult to shift gears |
| Worn or misadjusted clutch - Adjust clutch or change if necessary |
| Damaged or loose gear shift linkage - Service or replace shift linkage |
| Shift forks are worn or damaged - Install new shift forks |
| Worn gear shift mechanism - Replace worn components |
| Insufficient transmission oil pressure |
| Low transmission oil level - Correct the transmission oil level |
| Transmission fluid filter is dirty (if equipped) - Change or service the transmission fluid filter |
| Damaged relief valve - Replace valve as required |
| Transmission is making noise |
| Cracked or worn bearings - Replace the bearings |
| Not enough fluid in transmission - Fill up the transmission fluid |
| Dirty transmission oil - Transmission oil must be changed |
| Backlash is incorrect or gears are worn - Set backlash correctly or change the gears |
| Shift forks are worn or damaged - Shift forks need to be changed |
| Gaskets or seals are defective Gaskets or seal replacement required |
| Cracked transmission housing - Housing needs to be replaced |
| Hydraulics Troubleshooting |
| Hydraulic system overheated |
| The system pressure has not been corrected - Make the correct settings |
| Main relief valve failure or incorrect setting - Adjust the valve or replace if necessary |
| Hydraulic fluid contamination - Change hydraulic fluid |
| Air leaks in hydraulic system - Inspect the pump seals, suction line, and fittings |
| Low hydraulic system pressure |
| Not enough hydraulic oil in the system - Fill the hydraulic system with oil |
| Hydraulic oil filter element clogging - Service the hydraulic filter or change if required |
| Defective hydraulic pump - Flow-rate pump and change pump if necessary |
| Faulty or incorrect setting hydraulic spool valve - Change or set correctly |
| Faulty hydraulic cylinder - Check the hydraulic cylinder parts for damage or wear and replace if necessary |
| Hydraulic lines are leaking - Inspect hydraulic system for leaks and repair it |
| 3-point hitch does not raise or raises very slowly |
| Hydraulic fluid level is insufficient - Check and refill the hydraulic fluid |
| Cold hydraulic oil - Warm up the oil |
| Hydraulic fluid filter clogging - Install a new hydraulic filter element |
| Hydraulic pump is defective - Test the pump flow rate and change pump if required |
| Main relief valve incorrect adjustment or failure - Adjust relief valve or change if required |
| Defective or not adjusted hydraulic control valve - Adjust correctly or change |
| Hydraulic cylinder is broken - Check cylinder components for damage or wear and change if necessary |
| Loose or damaged suction line - Tighten or replace |
| Hitch won't lower or lowers slowly |
| Hydraulic spool valve block is faulty or out of adjustment - Set correctly or replace |
| Defective hydraulic cylinder - Inspect cylinder parts for wear or damage and replace if required |
| Hitch rock shaft is worn Replace the shaft |
| Mechanical parts of the hitch are damaged - Change defective or worn hitch components |
| Hitch lower or lift is jerky |
| Air enters in hydraulic system - Check the pump seals, suction pipe, and fittings |
| Hydraulic fluid is contaminated - Fill up with new hydraulic fluid |
| Hydraulic pump failure - Test the pump flow rate and change pump if required |
| Defective or not adjusted hydraulic spool valve - Adjust correctly or replace |
| Hydraulic cylinder is faulty - Inspect cylinder parts for wear or damage and replace if required |
| Steering System Troubleshooting |
| Steering wheel turns hard |
| Worn or improperly mounted steering column - Mount the steering column properly or change it |
| Air trapped in the steering system - Air-bleed steering system |
| Toe-in adjustment is incorrect - Adjust toe-in properly |
| Front tires are worn out - Install new tires |
| Faulty steering pump - Check the steering pump and replace if necessary |
| Worn or defective power steering valve assembly - Replace or repair steering valve as required |
| Worn steering box components - Repair power steering box |
| Low steering oil level - Fill up the steering oil |
| Steering system oil leakage - Tighten the steering hose and line joints |
| Excessive steering wheel play |
| Steering column shaft or coupling is worn out - Replace faulty component |
| Power steering valve assembly is worn or defective - Inspect and change as required |
| Faulty steering box parts - Defective power steering box components must be replaced |
| Steering pump is faulty - Replace or repair steering pump |
| Faulty or worn steering tie-rod ends or linkage - Replace failed component |
| Tractor pulls to left or right |
| Tires are not properly inflated - Inflate tires as required |
| Toe-in adjustment is incorrect - Adjust toe-in correctly |
| Steering linkage or tie-rod ends are worn - Replace failed component |
| Damaged steering box parts - Defective power steering box components must be replaced |
| Damaged or worn power steering valve assembly - Inspect and change as required |
| Incorrectly adjusted or damaged front hub bearings - Install new bearings or adjust it correctly |
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| Farm Tractors Technical Specifications |
