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Kubota B7100 Troubleshooting
The
Kubota B7100 compact utility tractor was manufactured from 1976 to 1985. The
tractor was designed in 2 versions: B7100E (2WD) and B7100D (4WD). The Kubota
B7100 tractor is equipped with a 46.5 cu.in (0.8L) Kubota D750 4-cycle vertical
3-cylinder water-cooled diesel engine.
The engine has a cylinder bore of 2.68" (68 mm), piston stroke of 2.76"
(70 mm), maximum power of 16 hp (11.9 kW), and 50.1 Nm (37.2 lb-ft) of
peak torque at 1800 rpm. The mechanical transmission consists of a dry
clutch and unsynchronized gearbox with 6 forward and 2 reverse gears.
The maximum travel speed (forward and reverse): 8.3 mph (13.4 km/h) /
4.2 mph (6.7 km/h). The open center hydraulic system includes a gear
pump with fluid flow rate of 3 gpm (11.4 lpm). The hydraulic system
pressure is 117 bar (1700 psi). The Kubota B7100 is equipped with a ball
screw type manual steering, independent brakes with dry drum, 4.00x9
(2WD) or 6.00x12 (4WD) front tires, and 7.00x16 (2WD) or 8.00x16 (4WD)
rear tires. The wheelbase is 48.8" (1240 mm) for 2-wheel drive models
and 49.2" (1250 mm) for 4-wheel drive models.
| Engine Troubleshooting |
| Engine doesn't start or hard to start |
| Fuel filter is clogged - Service or replace the filter |
| No fuel supply from the tank - Open the fuel supply valve |
| Air in fuel system - Air-bleed fuel system |
| Clogged fuel injectors - Clean or replace fuel injectors |
| Fuel injection pump is not operating properly - Install a new pump or rebuild |
| Bad engine compression - Inspect cylinder block and change damaged parts |
| Engine stops unexpectedly while running |
| Low coolant temperature - Engine is not warmed up to the required temperature |
| Water, dirt, or air in fuel system - Drain, flush, fill, and bleed system |
| Irregular fuel injection - Adjust fuel injection timing |
| Clogged fuel filter element - Replace filter element |
| Faulty or dirty injectors - Inspect fuel injectors and replace if necessary |
| Diesel engine stops after starting |
| Timing of fuel injection pump is not adjusted - Correct injection timing |
| Fuel filter is clogged - Change filter element |
| Faulty fuel injector nozzles - Check and change nozzles as required |
| Defective fuel injection pump - Replace injection pump or repair it |
| Air cleaner is clogged - Install new cleaner element or replace it |
| Low idle speed setting is incorrect - Normalize low idle speed |
| Defective fuel injection pump - Install a new pump or rebuild |
| Fuel injector nozzles are defective or dirty - Replace fuel injector nozzles |
| The valve clearance is incorrect - Have it adjusted |
| Lack of engine coolant - Fill cooling system to proper level. Check for coolant leaks |
| Cooling system parts are defective or system is dirty - Change faulty components or service cooling system |
| Engine oil insufficient - Check and refill engine oil |
| Fan belt is broken or belt tension is unadjusted - Adjust properly or replace the belt |
| Thermostat is defective - Test thermostat opening temperature, replace as required |
| Engine power is insufficient |
| Fuel injectors are damaged or dirty - Test fuel injectors and change if necessary |
| Incorrect fuel injection pressure - Test fuel injection pressure and adjust it correctly |
| Dirty air filter - Service or change air filter |
| Dirty oil filter - Change or service engine oil filter |
| Engine overloaded - Load reducing required |
| Excessive valve clearance - Adjust valve clearance |
| Incorrectly set low idle speed - Adjust as required |
| Fuel hoses or pipes are clogged - Fuel pipes and hoses need to be cleaned |
| Loss of compression: Valves are damaged or leaking - Valve replacement required |
| Timing of fuel injection pump is wrong - Check and correct adjustments |
| Clogged or damaged injector nozzles - Inspect injector nozzles and change if required |
| Engine oil insufficient - Fill up the oil to required level |
| Engine is not warmed up to the required temperature - Warm up the engine as required |
| Crankshaft or main bearings wear - Change or repair worn components |
| Piston rings failure - Have piston rings replaced |
| Loose flywheel bolts - Check flywheel bolts and tighten properly |
| Engine oil consumption is too high |
| External oil leaks: Gaskets or seals are excessively worn - Replace worn parts to avoid leaks |
| Improper oil viscosity - Fill up with the correct oil viscosity |
| Worn or broken piston rings - Change piston rings |
| Valve guides and stems are worn - Install new valves |
| Scuffed cylinder liners or pistons - Check pistons and liners, install new parts as required |
| Electrical System Troubleshooting |
| Battery will not charge |
| Worn-out battery - Replace the battery |
| Bad battery cable harness - Inspect cables for malfunctions, repair or change |
| Battery cables and terminals are loose or corroded - Service or tighten battery terminals and cables |
| Belt slipping or wrong belt tension adjustment - Install new belt or adjust belt tension as required |
| Starter motor cranks slow |
| Battery power is low - Battery is drained, charge it |
| Battery is not holding charge - Service battery or replace it |
| Battery wiring harness damage - Inspect battery wiring for damage, replace or repair |
| Corroded or loose battery terminals and cables - Tighten or service cables and terminals |
| Low battery capacity - Low battery charging, charge as required |
| Drained or worn battery - Battery needs to be recharged or replaced |
| Faulty starter motor - Change or repair starter |
| Battery cables are disconnected or incorrectly connected - Check cables and reconnect it correctly |
| Transmission Troubleshooting |
| Gear hard to shift |
| Clutch is not adjusted or faulty - Adjust correctly or replace |
| Gear shift linkage is loose or broken - Service or replace shift linkage |
| Bent or worn shift forks - Replace defective shift forks |
| Defective gearshift mechanism - Replace defective components |
| Low transmission oil pressure |
| Insufficient fluid supply - Fill system with correct transmission fluid level |
| Clogged transmission fluid filter element (if fitted) - Change or service the transmission fluid filter |
| Relief valve is faulty - Replace the valve |
| Bearings are worn or cracked - Faulty bearings should be changed |
| Insufficient oil supply - Checking transmission oil level and add if necessary |
| Dirty transmission oil - Transmission oil must be changed |
| Improper backlash or damaged gears - Set backlash properly or change the gears |
| Bent or worn shift forks - Shift forks need to be replaced |
| Transmission fluid leakage |
| Gaskets or seals are damaged - Change defective seal or gaskets |
| Transmission case is cracked - Replace case or transmission assembly |
| Hydraulics Troubleshooting |
| Hydraulic system is overheated |
| Hydraulic system pressure is unadjusted - Adjust the pressure as required |
| Main relief valve failure or incorrect setting - Adjust relief valve or change if required |
| Hydraulic fluid is dirty - Hydraulic fluid change required |
| Aeration in hydraulic system - Check the pump seals, suction pipe, and fittings |
| Hydraulic oil pressure too low |
| Lack of hydraulic oil - Add oil to the hydraulic system |
| Hydraulic fluid filter is clogged - Service the hydraulic filter or change if required |
| Hydraulic pump malfunction - Check pump flow and change pump if necessary |
| Hydraulic control valve is defective or set improper - Change or adjust properly |
| Hydraulic cylinder is defective - Check cylinder components for damage or wear and change if necessary |
| Leakage in hydraulic lines - Find leaks in the system and fix it |
| Hitch cannot be lifted or lifting is too slow |
| Lack of hydraulic fluid - Check and refill the hydraulic fluid |
| Cold hydraulic fluid - Warm up the fluid |
| Hydraulic oil filter clogging - Clean the hydraulic filter element or replace if necessary |
| Defective hydraulic pump - Test the pump performance and change pump if required |
| Main relief valve is defective or unadjusted - Adjust relief valve or change if required |
| Hydraulic control valve block is defective or set improper - Adjust properly or replace |
| Hydraulic cylinder malfunction - Check the hydraulic cylinder parts for damage or wear and replace if necessary |
| Broken or loose suction line - Retighten or change |
| 3-point hitch drops slowly or won't drop |
| Hydraulic spool valve block is not set properly or defective - Replace or set properly |
| Hydraulic cylinder is defective - Inspect the hydraulic cylinder parts for damage or wear and replace if required |
| Worn hitch cross shaft - Install a new shaft |
| The hitch has internal mechanical malfunctions - Replace damaged or worn hitch parts |
| 3-point hitch lift or lower is jerky |
| Aeration in hydraulic system - Inspect the pump seals, suction line, and fittings |
| Hydraulic fluid is dirty - Hydraulic fluid change required |
| Hydraulic pump malfunction - Test the pump performance and change pump if required |
| Faulty or incorrect setting hydraulic spool valve - Adjust properly or change |
| Defective hydraulic cylinder - Check the hydraulic cylinder parts for damage or wear and replace if necessary |
| Steering System Troubleshooting |
| Hard Steering |
| Steering knuckle or steering column is stuck - Inspect steering column and knuckle, replace worn parts |
| Steering gearbox components are worn - Replace defective components of steering gearbox |
| Faulty drag link or tie rod - Replace or repair |
| Insufficient lubrication in steering box - Need to lubricate the gearbox |
| Not adjusted toe-in alignment - Check and adjust toe-in |
| Tires are not correctly inflated - Inflate tires as necessary |
| Excessive steering wheel free play |
| Steering column bearing or shaft is worn - Change faulty parts |
| Steering linkage assembly is worn or loose - Repair or replace steering linkage |
| Worn steering gearbox bearings - Replace the bearings |
| Front wheel hub bearings or steering knuckles are worn - Change hub bearings or knuckles |
| Damaged or worn steering tie-rod ends - Change faulty part |
| Tractor pulls to right or left |
| Worn or loose steering linkage assembly - Repair or replace steering linkage |
| Defective steering knuckle bushing - Replace knuckle bushing |
| Uneven tire pressure - Inflate the tires properly |
| Toe-in adjustment is incorrect - Adjust toe-in correctly |
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| Farm Tractors Technical Specifications |
