Home / Farm Tractors / Kubota Tractors / Kubota L305

Kubota L305 Troubleshooting

The Kubota L305 is a compact utility tractor from L-series. This model was manufactured between 1979 and 1985. The Kubota L305 tractor is equipped with Kubota D1301-A vertical 4-cycle 3-cylinder diesel engine.

A 79.3 cubic inches (1.3 L) engine has a cylinder bore of 3.23" (82 mm), piston stroke of 3.23" (82 mm), and rated power of 30 hp (22.5 kW). The mechanical transmission includes a dry single-plate clutch and sliding mesh gearbox with 8 forward and 2 revers gears. Max. forward speed - 12.7 mph (20.4 kph), maximum reverse speed - 6.2 mph (10.1 kph).

The open center hydraulic system includes a gear pump with a flow rate of 6.4 gpm (24.2 lpm). The hydraulic pressure is 155 bar (2250 psi). The L305F tractors (2WD) are equipped with 7.00x16 front tires and 12.4x24 rear tires. The 8.3x16 front tires and 13.6x24 rear tires are used for L305DT tractors (4WD). The wheel base is 72.8" (1840 mm). The Kubota L305 is compatible with Kubota L1720 front end loader with lift capacity to full height of 1495 lbs (680 kg).

Engine Troubleshooting
Engine is not starting or hard starting
Fuel filter is clogged - Clean or change the filter
Closed fuel supply valve - Open supply valve to inject fuel
Water, dirt, or air in fuel system - Drain, flush, fill, and bleed system
Fuel injectors are clogged or faulty - Check fuel injectors and replace if required
Fuel injection pump is damaged - Replacement or repair required
Bad compression - Check cylinder block and replace worn parts
Engine shuts off unexpectedly during operation
Coolant temperature is low - Normalize the temperature by warming up the engine
Air in fuel system - Air-bleed fuel system
Improper fuel injection - Fuel injection settings required
Fuel filter clogging - Change filter element
Fuel injectors are damaged or dirty - Change fuel injectors
Engine starts but then shuts off
Fuel injection pump timing is incorrect - Fuel pump timing settings need to be corrected
Dirty fuel filter element - Change the filter element
Fuel injector nozzles fault - Change or clean injector nozzles
Fuel injection pump is damaged - Change or repair the pump
Air cleaner is clogged - Install new cleaner element or replace it
Engine stalls at low idle speed
Incorrectly set low idle speed - Correct low idle settings
Fuel injection pump is broken - Rebuild or replace pump
Fuel injector nozzles fault - Check and change nozzles as required
Valve clearance is out of adjustment - Adjust valve clearance
Engine overheated
Engine coolant is insufficient - Fill the cooling system. Repair any leaks if necessary
Cooling system is dirty or cooling components are damaged - Change faulty components or flush the cooling system
Not enough engine oil - Check oil level and add oil as required
Incorrect fan belt tension or broken belt - Adjust properly or change the belt
Thermostat is defective - Replace the thermostat
Reduced engine power
Fuel injectors are damaged or dirty - Inspect fuel injectors and replace if necessary
Fuel injection pressure is incorrect - Test fuel injection pressure and adjust it correctly
Air filter is clogged - Replace or service air filter element
Clogged oil filter - Clean or change engine oil filter
Engine overload - Change to lower gear or reduce load
The valve clearance is incorrect - Correct valve clearance
Low idle speed set incorrectly - Correct low idle settings
Dirt in the fuel pipes or hoses - Fuel pipes and hoses need to be cleaned
Engine compression is insufficient: Leaking or faulty valves - Change the valves
Engine knocking sound or abnormal noise
Unadjusted fuel injection pump timing - Check the fuel injection pump timing setting
Clogged or defective injector nozzles - Service or replace nozzles if required
Engine oil level is insufficient - Fill the crankcase with engine oil
Engine is not fully warmed up - Warm up the engine as required
Crankshaft or main bearings are worn out - Repair or replace defective parts
Broken or defective piston rings - Install new piston rings
Loose flywheel bolts - Inspect flywheel bolts and tighten properly
High oil consumption
Oil leaks: Seals or gaskets are wearing excessively - Install new components
Improper oil viscosity - Fill up with the correct oil viscosity
Stuck or worn piston rings - Have piston rings replaced
Damaged valve guides or valve stems - Replace the valves
Pistons or cylinder liners are scuffed - Inspect liners and pistons, change as necessary

Electrical System Troubleshooting
Battery is not charging
Faulty cell in battery - Battery change required
Damaged battery wiring harness - Inspect wiring for damage, replace or repair
Loose or corroded terminals and cables - Service or tighten battery terminals and cables
Defective belt or improperly adjusted belt tension - Change belt or adjust belt tension properly
Starter cranks slow
Low battery output voltage - Charge the battery
Battery is draining quickly - Service or replace the battery
Damaged battery cable harness - Check electrical cables for damage, repair or replace
Loose or corroded battery cables and terminals - Clean or tighten terminals and cables
Starter motor is not working
Low battery output voltage - Low battery charging, charge as required
Drained or defective battery - Need to charge or replace the battery
Starter motor failure - Starter should be replaced
Incorrectly connected or disconnected wires - Check battery wires and connect correctly

Transmission Troubleshooting
Hard shifts
Worn or incorrectly adjusted clutch - Clutch needs to be replaced or adjusted
Gear shift linkage is stuck or damaged - Change or repair shift linkage
Worn or damaged shift forks - Replace defective shift forks
Worn gear shift mechanism - Replace worn components
Transmission oil pressure is insufficient
Insufficient oil supply - Check transmission oil level and add oil as required
Transmission oil filter clogging (if fitted) - Replace or service transmission oil filter
Faulty relief valve - Replace relief valve as required
Transmission is making noise
Damaged or worn bearings - Bearings replacement required
Not enough oil in transmission - Fill up the transmission oil
Transmission fluid contamination - Change transmission fluid
Improper backlash or damaged gears - Change the gears or adjust backlash correctly
Shift forks are damaged or worn - Replace the shift forks
Transmission fluid leakage
Worn gaskets or seals - Install new components
Cracked transmission case - Install a new transmission case

Hydraulics Troubleshooting
Hydraulic system is overheated
Incorrect hydraulic pressure adjustments - Adjust correctly
Defective or misadjusted main relief valve - Adjust relief valve or change if required
Dirty hydraulic fluid - The fluid must be changed
Air in hydraulic system - Check the pump seals, suction line, and fittings
Hydraulic fluid pressure is insufficient
Hydraulic fluid level is low - Need to add fluid
Hydraulic oil filter is dirty - Change the hydraulic filter element or service if required
Damaged hydraulic oil pump - Test the pump performance and change pump if required
Hydraulic spool valve block is defective or set improper - Replace or adjust correctly
Hydraulic cylinder malfunction - Inspect cylinder components for damage or wear and change if required
Hydraulic lines are leaking - Identify leaks in the system and repair it
3-point hitch does not raise or raises very slowly
Hydraulic fluid level is insufficient - Fill the hydraulic system with oil
Cold hydraulic oil - Warm up the oil
Hydraulic oil filter clogging - Clean or change hydraulic filter
Hydraulic pump is faulty - Check hydraulic pump flow and replace pump if necessary
Main relief valve malfunction or incorrect adjustment - Adjust relief valve or change if required
Defective or incorrect setting hydraulic control valve block - Change or adjust properly
Hydraulic cylinder malfunction - Inspect cylinder components for wear or damage and change if required
Broken or loose suction line - Retighten or change
Hitch not dropping or hitch drops slowly
Hydraulic spool valve block is faulty or out of adjustment - Change or adjust properly
Hydraulic cylinder is defective - Check cylinder components for wear or damage and change if necessary
Lift arm shaft is worn - Replace the shaft
Mechanical parts of the hitch are damaged - Replace worn or faulty hitch components
Hitch is lowered or raised jerkily
Air leaks in hydraulic system - Check the suction line, pump seals, and fittings
Dirty hydraulic fluid - The fluid must be changed
Faulty hydraulic oil pump - Check pump performance and change it if necessary
Hydraulic spool valve block is defective or set improper - Replace or adjust properly
Defective hydraulic cylinder - Inspect the hydraulic cylinder parts for damage or wear and replace if required

Steering System Troubleshooting
Stiff steering
Steering column is defective or incorrectly installed - Steering column must be installed correctly or replaced
Aeration in steering system - Bleed air from system
Improper toe-in - Adjust toe-in properly
Tires are incorrectly inflated - Inflate as required
Steering pump stopped working - Check the steering pump and replace if necessary
Power steering valve has wear or malfunction - Repair or replace the steering valve
Damaged steering box parts - Defective parts of power steering box must be replaced
Lack of steering fluid - Need to add steering oil
Oil leakage in the steering system - Retighten steering hose and line connections
Steering wheel has too much free-play
Steering column shaft or coupling is worn out - Replace defective component
Power steering valve is defective or worn - Inspect and change as required
Damaged steering box parts - Change defective steering box parts
Steering pump not working - Steering pump needs to be repaired or replaced
Worn or faulty steering tie-rod ends or linkage - Replace damaged component
Tractor pulls to left or right
Tire pressure is low - Tires need to be inflated
Toe-in adjustment is incorrect - Adjust toe-in properly
Worn or faulty steering tie-rod ends or linkage - Replace failed part
Damaged steering box parts - Replace defective parts of power steering box
Power steering valve has wear or damage - Check and replace as required
Front hub bearings are damaged or incorrectly adjusted - Replace or adjust the bearings correctly



Farm Tractors Technical Specifications
JD 1026R JD 3650 JD 6400 JD 7810
FORD 1320 FORD 2810 FORD 3930 FORD 5600
MF 250 MF 690 MF 3060 MF 6180
NH TC48DA NH M100 NH T7550 NH 8560
CASE IH 495 CASE IH 1255XL CASE IH 2140 CASE IH 2294