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Kubota B7100HST Troubleshooting
The
Kubota B7100HST is a 2WD or 4WD compact utility tractor. This model was
manufactured between 1977 and 1997. The tractor was designed in 2 versions:
B7100HST-E (2WD) and B7100HST-D (4WD).
The Kubota B7100HST powertrain system components: a 46.5 cu.in (0.8L)
Kubota D750 4-cycle vertical 3-cylinder indirect injection naturally
aspirated water-cooled diesel engine with a maximum power of 16 hp (11.9
kW), and two-range hydrostatic transmission with infinite forward and
reverse gears.
Max forward speed: 3.5 mph (5.7 km/h) using low range or 9.1 mph (14.5
km/h) using high range, and max reverse speed: 2.4 mph (3.9 km/h) using
low range or 6.2 mph (10.1 km/h) using high range. The open center
hydraulic system used a gear pump with fluid flow rate of 3 gal/min
(11.4 l/min). The hydraulic pressure is 117 bar (1700 psi).
The two-wheel drive models are equipped with 4.00x9 front tires and
7.00x16 rear tires. The 6.00x12 (AG) or 20.5x8.00-10 (Turf) front tires
and 8.00x16 (AG) or 29x12.00-15 (Turf) rear tires are used for tractors
with four-wheel drive. The wheelbase is 54.6" (1390 mm) for 2WD models
and 55.1" (1400 mm) for 4WD models. The Kubota B7100HST is compatible
with a Kubota B1630C front-end loader with lift capacity to full height
of 510 lbs (230 kg) and breakout force of 780 lbs (353 kg).
| Engine Troubleshooting |
| Engine will not start or hard to start |
| Fuel filter is dirty - Replace the filter element |
| Closed fuel supply valve - Open supply valve to inject fuel |
| Air in fuel pipes - Bleed fuel pipes |
| Faulty or dirty injectors - Change fuel injectors |
| Damaged fuel injection pump - Replace or repair injection pump |
| Engine has low compression - Inspect cylinder block and change worn parts |
| Engine stalls during operation |
| Engine is cold - Warm up the engine |
| Air in fuel lines - Bleed fuel lines |
| Bad fuel injection - Check and adjust |
| Fuel filter is dirty - Filter maintenance required |
| Fuel injectors are defective or dirty - Check fuel injectors and replace if required |
| Diesel engine stalls after starting |
| Incorrect setting of fuel injection pump timing - Check the fuel injection pump timing setting |
| Fuel filter is dirty - Change filter element |
| Fuel injector nozzles fault - Replace fuel injector nozzles |
| Fuel injection pump is damaged - Repair or change injection pump |
| Dirty air cleaner element - Service or change air cleaner |
| Engine stops at low idle speed |
| Incorrect low idle speed adjustment - Correct the settings |
| Fuel injection pump damage - Rebuild or change fuel pump |
| Clogged or damaged injector nozzles - Service or replace nozzles if required |
| The valve clearance is not adjusted - Adjust valve clearance |
| Low engine coolant - Top up coolant. Check and repair damage to the cooling system if required |
| Cooling system is dirty or cooling components are damaged - Flush cooling system or replace faulty parts |
| Engine oil level low - Checking oil level and add if necessary |
| Fan belt tension is not adjusted or belt is worn - Replace or adjust belt tension properly |
| Thermostat malfunction - Install new thermostat |
| Diesel engine is losing power |
| Fuel injectors are defective or dirty - Check fuel injectors and replace if required |
| Fuel injection pressure is incorrect - Check the fuel injection pressure and adjust if necessary |
| Air filter element is clogged - Clean or replace the air filter element |
| Oil filter element is dirty - Change or clean engine oil filter element |
| Diesel engine is overloaded - Shift to lower gear or reduce the load |
| Valve clearance is wrong - Need to adjust valve clearance |
| Low idle speed setting is not correct - Normalize low idle speed |
| Fuel hoses or pipes are dirty - Clean fuel hoses and pipes |
| Engine compression too low: Valves are faulty or leaking - Change the valves |
| Unadjusted fuel injection pump timing - Adjust injection timing |
| Dirty or defective injector nozzles - Install a new set of well-balanced nozzles |
| Insufficient engine oil - Fill up the engine oil |
| Engine is not fully warmed up - Normalize the temperature by warming up the engine |
| Main bearings or crankshaft failure - Need to install new components |
| Broken or defective piston rings - Replace the piston rings as required |
| Flywheel screws are loose - Tighten the screws firmly |
| High engine oil consumption |
| Oil leakage: Seals or gaskets are wearing excessively - To repair leaks, replace worn parts |
| Oil viscosity is incorrect - Use oil of correct viscosity |
| Seized or wear piston rings - Change the piston rings as required |
| Valve stems or guides are damaged - Valves need to be changed |
| Scuffed pistons or cylinder liners - Check liners and pistons, replace as required |
| Electrical System Troubleshooting |
| Battery does not charge |
| Battery is worn - Battery replacement required |
| Battery cable harness damage - Check battery cables for damage, change or repair |
| Loose or corroded cables and terminals - Tighten or clean cables and terminals |
| Belt is worn or belt tension is incorrectly adjusted - Change belt or properly adjust belt tension |
| Low battery capacity - Low battery charging, charge as required |
| Battery does not hold charge - Service battery or change it |
| Bad battery electrical wire harness - Check wires for malfunctions, repair or replace |
| Corroded or loose battery cables and terminals - Service or tighten battery cables and terminals |
| Battery power is low - Recharge the battery |
| Discharged or faulty battery - Change or recharge battery |
| Starter motor is defective - Repair or replace starter |
| Disconnected or incorrectly connected cables - Inspect battery cables and connect correctly |
| Hydrostatic Transmission Troubleshooting |
| Excessive HST transmission noise |
| Fluid level is too low or fluid is dirty - Change fluid or top up to proper level |
| Speed control rod linkage is damaged or unadjusted - Adjust or repair rod linkage |
| Relief valve is faulty - Change the valve |
| Transmission overload - Reduce loading |
| Worn or damaged parts of the transmission - After disassembly and checking, replace worn components |
| Transmission fluid overheats |
| Oil level is low - Add transmission oil as required |
| Transmission fluid filter is plugged - Change or clean the transmission fluid filter |
| Cooling components are damaged or clogged - Inspect all cooling components and service or change if necessary |
| Excessive transmission load - Load needs to be reduced |
| Fluid level is low - Fill system with correct transmission fluid level |
| Charge pressure is insufficient - Test charge pressure |
| Defective or worn relief valve - Install a new valve |
| Broken gaskets or seals - Seals and gaskets replacement required |
| High pressure inside the transmission housing - Repair or replace worn parts |
| Oil return tube is clogged - Inspect tube and service if required |
| Hydraulics Troubleshooting |
| Hydraulic system overheated |
| Improper hydraulic system pressure setting - Set the pressure properly |
| Main relief valve incorrect adjustment or failure - Set up or change the relief valve |
| Hydraulic oil contamination - Change the oil |
| Air leaks in hydraulic system - Check the suction line, pump seals, and fittings |
| Hydraulic fluid pressure is low |
| Hydraulic oil level is insufficient - Fill the hydraulic system with oil |
| Hydraulic fluid filter element clogging - Change the hydraulic filter element or service if required |
| Faulty hydraulic oil pump - Check hydraulic pump flow and replace pump if necessary |
| Defective or not adjusted hydraulic control valve - Adjust properly or change |
| Hydraulic cylinder failure - Inspect the hydraulic cylinder parts for damage or wear and replace if required |
| Hydraulic piping leaks - Identify leaks in the system and repair it |
| Three-point hitch lifting is too slow or cannot be lifted |
| Hydraulic fluid level is low - Add fluid to the hydraulic system |
| Cold oil in hydraulic system - Wait for oil to warm up |
| Hydraulic fluid filter clogging - Change hydraulic filter element or clean if necessary |
| Hydraulic pump is defective - Check the pump capacity and replace pump if required |
| Main relief valve failure or incorrect setting - Set up or change the relief valve |
| Damaged or incorrect adjusted hydraulic control valve - Change or set correctly |
| Hydraulic cylinder is defective - Inspect cylinder parts for wear or damage and replace if required |
| Suction pipe is damaged or loose - Repair or change |
| 3-point hitch won't drop or drops slowly |
| Hydraulic control valve block is not set properly or defective - Set correctly or replace |
| Faulty hydraulic cylinder - Inspect cylinder components for wear or damage and change if required |
| Hitch rock shaft is damaged - Replace the shaft |
| Internal mechanical malfunction with hitch - Replace faulty or worn hitch components |
| Hitch is lowered or raised jerkily |
| Air trapped in the hydraulic system - Check the suction line, pump seals, and fittings |
| Hydraulic fluid is contaminated - Fill up with new hydraulic fluid |
| Hydraulic pump failure - Check the pump performance and replace it if required |
| Defective or not adjusted hydraulic control valve - Adjust correctly or replace |
| Hydraulic cylinder failure - Check cylinder components for damage or wear and change 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 |
