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Home / Wheel Loaders / Case Wheel Loaders / Case 721C

Case 721C Troubleshooting

The Case 721C wheel loader driveline system components: Case 6T-830 four-stroke vertical six-cylinder direct injection turbocharged liquid-cooled diesel engine with a rated power of 152 hp (113 kW), and autoshift transmission with 4 forward and 3 reverse gears. The hydraulic system has a vane-type pump with a rated capacity of 42.9 gal/min (163 l/min). The Case 721C is equipped with an articulated steering system, hydraulic wet disc brakes, and 20.5x25 tires. The wheel loader has a max lift height of 150" (3810 mm) and breakout force of 33000 lbs (14970 kg). The rated operating capacity is 9597 lbs (4353 kg), and tipping load is 19195 lbs (8706 kg).

Engine Troubleshooting

Engine hard to start or will not start
Air in the fuel system - Air bleeding.
Fuel filter plugging - Install new filter element.
Faulty or dirty injection nozzles - Inspect nozzles and replace if necessary.
Water in the fuel system - Change fuel and repair fuel system.
The valve clearance is not adjusted - Check and adjust as required.
Damaged fuel injection pump - Repair or install new pump.

Diesel starts but immediately shuts off
Air filter is dirty - Replace or clean air filter element.
Fuel filter element is dirty - Change filter element.
Fuel injection pump has loose connections - Tighten the connections.
Fuel injectors are faulty or clogged - Test and replace fuel injectors if necessary.
Fuel injection pump is not operating properly - Replace or rebuild injection pump.

Engine stalls after running
Engine is not preheated - Warm up the engine.
Fuel filter element is dirty - Service or replace the filter.
There is air in the fuel system - Bleed the system.
Damaged or dirty injection nozzles - Change fuel injection nozzles.
Improper fuel injection timing - Set it up as required.

Engine stops at low idle speed
Incorrectly adjusted low idle speed - Adjust as required.
Fuel injection pump malfunctioning - Rebuild or change fuel pump.
Defective fuel injectors - Inspect fuel injectors and change as required.
Incorrect valve clearance - Adjust valve clearance.

Low engine power
Clogged air cleaner - Clean or change cleaner.
Faulty fuel injection nozzles - Change fuel injection nozzles.
Incorrect fuel injection pressure - Correct the pressure settings.
Valve clearance is wrong - Need to adjust valve clearance.
Wrong adjustment of low idle speed - Adjustment required.
Dirty fuel hoses or lines - Fuel hoses and lines must be clean.
Leaking cylinder head gasket - Replace the gasket as required.
Piston rings are worn or defective - Install new piston rings.

Engine overheats
Low engine coolant - Fill radiator to proper level and check components for faults.
Low engine oil level - Fill up the engine oil.
Clogged radiator fins or damaged radiator cap - Clean radiator or change cap.
Excessive wear of the fan belt - Belt replacement is recommended.
Diesel engine is overloaded - Load reducing required.

Insufficient oil pressure
Low oil level - Check oil level and add oil as required.
Oil filter element is dirty - Change or clean engine oil filter element.
Oil grade or viscosity is wrong - Drain crankcase and refill with correct oil.
Incorrect oil clearance in crankshaft bearing - Bearing needs to be changed.
Oil pump is defective - Install a new pump.

Engine noise or knocking
Insufficient engine oil - Check oil level and add oil as required.
Engine is not warmed up to required temperature - Warm up engine as required.
Improper fuel injection timing - Adjust the pump as required.
Low idle speed set incorrectly - Need to adjust idle speed.
Damaged or clogged injectors - Replace fuel injectors.
Connecting rod misalignment or failure - Need to change or align the connecting rod.
Scored or worn pistons - Replace the pistons.

Transmission Troubleshooting

Lack of transmission oil pressure
Low oil level - Check transmission oil level and add oil as required.
Transmission fluid filter element clogging (if equipped) - Replace or service transmission fluid filter.
Relief valve failure - Install a new valve.

Transmission makes excessive noise
Insufficient transmission oil - Check and refill the transmission oil.
Transmission oil contamination - Transmission oil change required.
Gears are defective or backlash is improper - Replace defective gears or set backlash properly.
Worn or cracked bearings - Faulty bearings should be replaced.
Worn or damaged gear shift forks - Change the shift forks.
Shaft splines are stuck or worn out - Shaft need to be replaced.

Gear shift is hard
Gear shift linkage is corroded or worn - Shift linkage need to be replaced.
Shift forks are bent or worn out - Change the shift forks.
Worn parts of the gear shifting mechanism - Change worn parts.
Clutch is worn or not adjusted - Adjust or replace the clutch.

Transmission oil leaks
Transmission oil level is high - Correct the oil volume.
Broken seals or gaskets - Replace worn seal or gaskets.

Hydraulics Troubleshooting

Hydraulic system overheating
Hydraulic pressure incorrectly adjusted - Correct adjustment is required.
Faulty or improperly adjusted main relief valve - Adjust or change relief valve.
Hydraulic oil contamination - Hydraulic oil change required.
Hydraulic fluid level is insufficient - Fill the hydraulic system with oil.
Hydraulic pump is faulty - Replace or repair pump if necessary.

Boom does not raise or lower
Lift controls are faulty - Change or repair.
Hydraulic pump failure - Replace or repair pump if necessary.
Hydraulic control valve is defective - Change or repair hydraulic valve.
Damaged hydraulic cylinder - Repair or replace hydraulic cylinder.
Hydraulic oil is insufficient - Fill the system to proper hydraulic oil level.

Bucket fails to tilt
Bucket tilt controls malfunction - Change or repair.
Hydraulic pump malfunction - Repair or change pump if required.
Hydraulic control valve is faulty - Replace or repair the valve.
Bucket cylinder is faulty - Install a new cylinder or repair it.
Insufficient hydraulic fluid - Fill up the hydraulic fluid.

Bucket or lift arm is moving slowly
Faulty hydraulic oil pump - Check the pump performance and replace it if required.
Hydraulic cylinder oil leakage - Change cylinder piston seals.
Low hydraulic oil level - Checking hydraulic oil level and add if necessary.
Hydraulic control valve is defective or set improper - Repair or adjust correctly.
Hydraulic pressure loss - Correct setting is required.

Bucket or boom is moving jerkily
Air trapped in hydraulic system - Bleed air from hydraulic system.
Hydraulic oil filter clogging - Clean or replace the filter.
Hydraulic oil contamination - The oil must be changed.
Cylinder tube or rod scoring - Replace damaged component.

Hydraulic pump makes excessive noise
Lack of oil or hydraulic leakage - Add hydraulic oil or correct system leaks.
Clogged hydraulic filter - Service or change hydraulic filter.
Suction line is dirty - Suction line needs to be cleaned.
Pump sucks air - Bleed air from hydraulics.
Faulty pump components - Change or rebuild pump.

Electrical Troubleshooting

Battery does not charge
Loose or corroded wire connections - Service or tighten connections.
Defective battery terminal clamps - Change terminal clamps.
Bad cell in battery - Change the battery.
Loose or worn belt - Install a new belt or adjust belt tension.

Starter turns slowly
Low battery capacity - Recharge the battery.
Battery is draining quickly - Service battery or replace it.
Bad terminals or disconnected battery cables - Check cables and service or change terminals.

Starter motor won't turn
Battery is low or faulty - Need to charge or replace the battery.
Wire harness is disconnected or incorrectly connected - Check wire harness and connect as required.
Low battery capacity - Charge the battery.
Defective starter motor - Repair or change starter.

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