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Kubota M4950 Troubleshooting
The
Kubota M4950 utility tractor was manufactured from 1983 to 1993. This model has
two version: M4950F (2WD) and M4950DT (4WD). The Kubota M4950 powertrain system
components: a 170.3 cu.in (2.8 L) Kubota S2800-A six-cylinder liquid-cooled
diesel engine and fully synchronized transmission with 12 forward and 4 reverse
gears. The engine has a cylinder bore of 3.35" (85 mm), piston stroke of 3.23"
(82 mm), and rated power of 51 hp (38 kW). The maximum travel speed
(forward/reverse): 15.7 mph (25.3 kph) and 6.6 mph (10.6 kph).
The open center hydraulic system has a gear pump with a rated capacity
of 9.3 gal/min (35 l/min). The hydraulic pressure is 181 bar (2630 psi).
The 2-wheel drive models are equipped with 6.0x16 front tires and
14.9x28 rear tires. The 8.3x24 front tires and 14.9x28 rear tires are
used for 4-wheel drive tractors. The Kubota M4950 tractor can be
equipped with Kubota M1840A
front-end loader with a lift capacity to full height of 2350 lbs
(1065 kg) and breakout force of 4400 (1995 kg).
| Engine Troubleshooting |
| Engine doesn't start or difficult to start |
| Fuel filter clogging - Clean the filter or install new filter element |
| The fuel shut-off valve is closed - Open fuel shut-off valve |
| Air trapped in fuel system - Bleed air |
| Dirty or damaged injectors - Inspect fuel injectors and replace if necessary |
| Faulty fuel injection pump - Change pump or rebuild it |
| Bad engine compression - Check and change damaged parts |
| Engine stops running unexpectedly |
| Engine not warmed up - Warm up the engine |
| Air in fuel system - Air-bleed fuel system |
| Uneven fuel injections - Repair or adjustment |
| Fuel filter is dirty - Clean the filter element |
| Dirty or damaged injectors - Change fuel injectors |
| Diesel starts but suddenly stops |
| Incorrectly set fuel injection pump timing - Fuel pump timing settings need to be corrected |
| Fuel filter is dirty - Clean or replace the filter |
| Fuel injector nozzles are damaged - Test injector nozzles and replace as required |
| Fuel injection pump is broken - Replace injection pump or repair it |
| Dirty air cleaner element - Install new cleaner element or replace it |
| Engine stalls when idling |
| Low idle speed set incorrectly - Need to adjust idle speed |
| Fuel injection pump is defective - Replacement or repair required |
| Fuel injector nozzles are defective or dirty - Test injector nozzles and replace as required |
| Incorrect valve clearance - Adjust valve clearance |
| Coolant level is low - Fill radiator to proper level. Check and repair damage to the cooling system if required |
| Cooling system parts are damaged or system is dirty - Replace faulty parts or flush the cooling system |
| Engine oil level is low - Fill up the engine oil |
| Incorrect fan belt tension or broken belt - Adjust as required or change belt |
| Thermostat is defective - Check thermostat, replace if necessary |
| Dirty or faulty injectors - Inspect fuel injectors and replace if necessary |
| Fuel injection pressure is wrong - Test fuel injection pressure and adjust it correctly |
| Clogged air filter element - Change or replace air filter element |
| Clogged oil filter - Service or change engine oil filter element |
| Engine overload - Reduce engine load |
| Valve clearance is wrong - Adjust valve clearance |
| Incorrectly adjusted low idle speed - Correct the settings |
| Dirty fuel hoses or pipes - Clean fuel system pipes and hoses |
| Engine losing compression: Valves are damaged or leaking - Change the valves |
| Engine knocking sound or abnormal noise |
| Incorrectly set fuel injection pump timing - Fuel injection pump timing adjustment needs to be corrected |
| Fuel injector nozzles fault - Install a new set of well-balanced nozzles |
| Engine oil insufficient - Check oil level and add oil as required |
| Engine is not warmed up to required temperature - Normalize the engine temperature |
| Main bearings or crankshaft wear - Worn parts replacement required |
| Damaged or defective piston rings - Piston rings replacement required |
| Loose flywheel bolts - Check flywheel bolts and tighten properly |
| Diesel engine consuming too much oil |
| Oil leaking: Gaskets or seals can be faulty - Change to repair leaks |
| Improper oil viscosity - Use correct viscosity oil |
| Stuck or worn piston rings - Piston rings need to be replaced |
| Valve stems and guides are worn - Change the valves |
| Worn cylinder liners or pistons - Inspect pistons and liners, change as required |
| Electrical System Troubleshooting |
| Battery will not charge |
| Battery dead cell - Change the battery |
| Bad battery electrical wire harness - Check wires for malfunctions, repair or replace |
| Loose or corroded battery cables and terminals - Terminals and cables need to be tightened or cleaned |
| Belt is defective or belt tension is improperly adjusted Adjust belt tension as required or replace belt |
| Battery power is low - Battery is drained, charge it |
| Battery won’t hold charge - Battery needs to be serviced or replaced |
| Bad battery wiring harness - Inspect wiring for malfunctions, replace or repair |
| Battery terminals and cables are loose or corroded - Tighten or clean cables and terminals |
| Low battery power - Recharge the battery |
| Discharged or worn battery - Need to charge or replace the battery |
| Damaged starter motor - Replace or repair starter |
| Battery cables are disconnected or incorrectly connected - Check cables and reconnect it correctly |
| Transmission Troubleshooting |
| Hard shifting |
| Clutch is not adjusted or faulty - Clutch adjustment or replacement required |
| Loose or broken gear shift linkage - Replace or repair the shift linkage |
| Bent or worn shift forks - Change the shift forks |
| Defective gearshift mechanism - Replace defective components |
| Insufficient transmission fluid pressure |
| Not enough fluid in transmission - Check transmission fluid level and add it as required |
| Transmission oil filter clogging (if fitted) - Change or clean the transmission oil filter |
| Relief valve sticking - Replace the valve |
| Transmission is excessively noisy |
| Cracked or worn bearings - Faulty bearings should be changed |
| Lack of transmission fluid supply - Fill up the transmission fluid |
| Dirty transmission oil - Transmission oil must be changed |
| Damaged gears or improper backlash - Replace gears or set backlash correctly |
| Worn or damaged shift forks - Replace defective shift forks |
| Seals or gaskets are damaged - Gaskets or seal replacement required |
| Cracked transmission housing - Housing needs to be replaced |
| Hydraulics Troubleshooting |
| Excessive hydraulic system heat |
| Hydraulic system pressure is not set correctly - Set the hydraulic pressure as required |
| Main relief valve malfunction or incorrect adjustment - Adjust relief valve or change if required |
| Hydraulic oil is contaminated - Fill up with fresh hydraulic oil |
| Air in hydraulic system - Inspect the pump seals, suction line, and fittings |
| Hydraulic oil pressure is low |
| Hydraulic oil level is low - Fill up the hydraulic oil |
| Hydraulic oil filter clogging - Clean the hydraulic filter element or replace if necessary |
| Faulty hydraulic oil pump - Test the pump performance and change pump if required |
| Hydraulic spool valve block is defective or set improper - Set properly or replace |
| Hydraulic cylinder malfunction - Inspect cylinder parts for wear or damage and replace if required |
| Leakage in hydraulic lines - Detect leaks in hydraulic system and repair it |
| 3-point hitch does not raise or raises very slowly |
| Not enough hydraulic fluid in the system - Add fluid to the hydraulic system |
| Hydraulic fluid is too cold - Allow fluid to warm |
| Hydraulic oil filter element clogging - Change hydraulic filter element or clean if necessary |
| Hydraulic pump failure - Check pump flow and install new pump if necessary |
| Main relief valve failure or incorrect setting - Adjust relief valve or change if required |
| Hydraulic control valve block is not set properly or defective - Change or adjust correctly |
| Defective hydraulic cylinder - Inspect the hydraulic cylinder parts for damage or wear and replace if required |
| Broken or disconnected suction line - Connect or replace |
| 3-point hitch fails to drop or drops slowly |
| Hydraulic control valve block is defective or set improper - Change or adjust properly |
| Hydraulic cylinder is broken - Check the hydraulic cylinder parts for damage or wear and replace if necessary |
| Damaged hitch rock shaft - Install a new shaft |
| Mechanical parts of the hitch are damaged - Change worn or damaged hitch components |
| Jerky lifting or lowering of 3-point hitch |
| Aeration in hydraulic system - Inspect the pump seals, suction line, and fittings |
| Contaminated hydraulic oil - Change hydraulic oil |
| Damaged hydraulic oil pump - Check pump flow and change pump if necessary |
| Faulty or incorrect setting hydraulic spool valve - Adjust properly or change |
| Hydraulic cylinder malfunction - Inspect cylinder parts for wear or damage and replace if required |
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| Farm Tractors Technical Specifications |
