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Case IH MX-120 Troubleshooting

The Case IH MX120 farm tractor was manufactured between 1997 and 2002. The Case IH MX 120 tractor is powered by 359 cu.in (5.9 L) Cummins B6T-590 six-cylinder turbocharged diesel engine with a rated power of 120 hp (89.5 kW).

The Case IH MX120 Maxxum is fitted with a 2 types of transmission. Type 1: 16x12 synchromesh transmission. Type 2: 20x12 (32x24 with creeper) partial powershift transmission. The maximum travel speed (forward/reverse): 23 mph (37 kph) and 13.7 mph (22.2 kph). The closed center pressure flow compensated hydraulic system has a pump with a rated capacity of 25 gpm (94.6 lpm).

The hydraulic system pressure is 203 bar (2950 psi). The 2WD models are equipped with 11.00x16 front tires and 18.4-R38 rear tires. The 480/70R26 front tires and 520/70R38 rear tires are used for 4WD tractors. The tractor is compatible with a Case IH L300 front loader with lift capacity to maximum height of 3850 lbs (1746 kg) and breakout force of 4900 lbs (2222 kg).

Diesel Engine Troubleshooting
Engine difficult to start or doesn't start

Air trapped in fuel system - Bleed air.
Fuel filter element clogging - Change filter element.
Fuel injection nozzles are dirty or defective - Change fuel injection nozzles.
Water or dirt in fuel system - Drain, flush, and service the system.
Valve clearance is wrong - Correct valve clearance.
Fuel injection pump failure - Rebuild or replace pump.

Engine starts and then shuts off

Plugged air filter - Change air filter element.
Fuel filter plugged - Clean or replace the filter.
Fuel injection pump leakage - Check the fuel injection pump for leaks and fix it.
Fuel injectors are dirty or defective - Clean fuel injectors or change it.
Fuel injection pump is not working correctly - Install a new fuel pump or repair.

Engine shuts off suddenly while running

Coolant temperature is low - Warm up engine as required.
Fuel filter plugging - Change the filter element.
Air trapped in fuel system - Bleed air.
Defective or clogged injection nozzle - Check and replace nozzles if required.
Incorrect adjustment of fuel injection pump timing - Adjust fuel injection pump as required.

Engine shuts off while idling

Incorrectly adjusted low idle speed - Correct the settings.
Fuel injection pump is not operating properly - Repair or install a new fuel pump.
Fuel injector fault - Change or clean fuel injectors.
The valve clearance is not adjusted - Adjustment procedure required.

Loss of engine power

Restricted intake air - Clean or replace element.
Faulty fuel injection nozzles - Clean or change injection nozzles.
Fuel injection pressure is wrong - Adjust pressure to proper level.
Excessive valve clearance - Need to adjust valve clearance.
Wrong adjustment of low idle speed - Adjust low idle speed.
Fuel lines or hoses clogging - Clean fuel system hoses and lines.
Cylinder-head gasket is broken - Gasket should be replaced.
Damaged or leaking piston rings - Change piston rings.

Engine overheated

Insufficient coolant fluid - Refill to the correct level and inspect system for leaks.
Not enough engine oil - Checking oil level and add if necessary.
Dirty radiator core or faulty radiator cap - Install new cap or clean radiator.
Broken or loose fan belt - Change as required.
Engine overload - Reduce load or shift to lower gear.

Oil pressure is low

Insufficient engine oil - Need to add oil.
Oil filter element is dirty - Service or replace engine oil filter.
Incorrect oil viscosity - Fill up with the correct oil viscosity.
Incorrect oil clearance in crankshaft bearing - Bearing replacement required.
Worn oil pump - Check and replace if necessary.

Engine noises or knocks

Insufficient engine oil - Checking oil level and add if necessary.
Low coolant temperature - Normalize the temperature by warming up the engine.
Improper fuel injection timing - Set up as recommended.
Incorrectly adjusted low idle speed - Adjust low idling as recommended.
Fuel injector fault - Test and replace fuel injectors if necessary.
Connecting rod is worn or misaligned - Align or replace connecting rod.
Pistons are worn or scored - Install new pistons.

Transmission Troubleshooting
Low transmission oil pressure

Insufficient transmission fluid - Add fluid to the transmission housing.
Transmission fluid filter element is clogged (if equipped) - Service or replace the transmission fluid filter.
Relief valve failure - Replace valve as required.

Excessive transmission noise

Insufficient transmission oil - Fill up the transmission oil.
Transmission fluid is dirty - Transmission fluid change required.
Gears are defective or backlash is improper - Install new gears and adjust backlash properly.
Bearings are cracked or worn - Bearings need to be replaced.
Damaged or worn gear shift forks - Shift forks need to be changed.
Worn or damaged shaft splines - Change the shaft.

Hard shifts

Rusty or worn gear shift linkage - Install a new gear shift linkage.
Worn or bent gear shift forks - Shift forks need to be replaced.
Gear shifting mechanism is defective - Defective parts must be replaced.
Clutch is out of adjustment or defective - Clutch replacement or adjustment required.

Transmission fluid leaks

High transmission fluid level - Drain the excess fluid.
Seals or gaskets are worn - Change defective gaskets or seal.

Hydraulic System Troubleshooting
Low hydraulic oil pressure

Low hydraulic oil level - Need to add oil.
Hydraulic oil filter is clogged - Hydraulic filter maintenance required.
Hydraulic pump not working - Repair or replace hydraulic fluid pump.
Incorrect setting hydraulic spool valve - Use the correct setting.
Hydraulic cylinder is broken - Replace or repair hydraulic cylinder.
Leaking hydraulic pipes - Identify leaks in the system and repair it.

Hydraulic system is too hot

Main relief valve failure - Change relief valve.
Hydraulic oil type is improper - Fill up with the proper type of oil.
Hydraulic fluid is dirty - Hydraulic fluid change required.
Air in the hydraulic system - Air bleeding.

Hitch won't raise or raises slowly

Excessive loading on the hitch - Reduce the load is required.
Low hydraulic fluid level - Add fluid as required.
Clogged hydraulic fluid filter element - Hydraulic filter maintenance required.
Hydraulic pump failure - Repair or replace hydraulic fluid pump.
Defective main relief valve - Relief valve must be changed.
Faulty hydraulic control valve - Repair or change hydraulic valve.
Hydraulic cylinder is defective - Repair or change hydraulic cylinder.
Suction line is loose or broken - Replace or repair.

Hitch won't drop or drops slowly

Hydraulic control valve block is out of adjustment - Control valve needs to be adjusted.
Hydraulic cylinder malfunction - Change or repair hydraulic cylinder.
Hitch is out of adjustment - Adjust as required.
Hitch rock shaft is damaged - Change the shaft.

Hitch drop or lift is jerky

There is air in the hydraulic system - Bleed hydraulic system.
Dirty hydraulic fluid - The fluid must be changed.
Damaged hydraulic pump - Replace or repair hydraulic oil pump.
Hydraulic control valve block is damaged - Repair or change hydraulic valve.
Broken hydraulic cylinder - Repair or replace hydraulic cylinder.

Steering System Troubleshooting
Steering is difficult

Incorrectly fitted or worn steering column - Refit or replace the steering column.
Air in the hydraulic steering system - Need to bleed air.
Improper toe-in - Check and adjust toe-in.
Uneven tire pressure - Inflate the tires properly.
Steering pump is faulty - Check the hydraulic steering pump and change if necessary.
Worn or stuck pump flow control valve - Service or replace flow control valve.
Lack of steering oil - Fill the steering system with oil.

Excessive steering wheel free play

Steering column shaft or coupling is worn out - Change faulty part.
Steering pump malfunction - Check the hydraulic steering pump and change if necessary.
Loose or worn steering linkage parts - Replace or repair steering linkage.

Front wheels wander to right or left

Tires have uneven wear - Replace the tires.
Improper toe-in - Adjust toe-in wheels.
Steering linkage components are loose or worn - Change or repair steering linkage.
Front wheel bearings are damaged or incorrectly adjusted - Adjust properly or replace bearings.

Electrical System Troubleshooting
Battery is not charging

Electrical wire connections are loose or corroded - Clean or tighten wiring connections.
Defective electrical terminal connectors - Change terminal connectors.
Battery dead cell - Battery replacement required.
Loose or defective belt - Belt needs to be adjusted or changed.

Starter motor turns slow

Battery power is low - Recharge the battery.
Battery drains quickly - Service charging system or install new battery.
Terminals are faulty or battery cables are disconnected - Connect wiring properly or install new terminals.

Starter motor is not working

Battery is drained or defective - Battery needs to be recharged or replaced.
Battery cables are disconnected or improperly connected - Inspect cables and connect properly.
Low battery power - Battery is drained, charge it.
Defective starter motor - Replace or repair starter.



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