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Caterpillar 257B Troubleshooting

The Cat 257B multi-terrain loader is powered by 134.1 cu.in (2.2L) Caterpillar 3024CT 4-cylinder turbocharged diesel engine with a rated power of 100 hp (74.6 kW) at 2600 rpm. The Caterpillar 257B is equipped with a 2-speed hydro transmission, vertical-lift loader boom, positive track drive, and 15" (380 mm) rubber track undercarriage. The hydraulic system has a pump with fluid flow rate of 15.6 gpm (60 lpm) or 26 gpm (100 lpm). The hydraulic pressure is 3335 psi (230 bar). The loader has a rated operating capacity of 1615 lbs (732 kg) and tipping load of 4620 lbs (2095 kg). The boom lifting force is 3683 lbs (1670 kg), and bucket breakout force is 3732 lbs (1693 kg).

Engine Troubleshooting

Engine hard to start or won't start
There is air in the fuel system - Bleed the system.
Fuel filter plugging - Change filter element.
Fuel injection nozzles are faulty or clogged - Replace injection nozzles.
Water or dirt in fuel system - Drain, flush, and service the system.
Valve clearance is not correct - Adjust valve clearance.
Faulty fuel injection pump - Install a new pump or rebuild.

Engine starts but then stops
Plugged air filter - Change or service air filter element.
Fuel filter plugging - Replace the filter element.
Fuel injection pump leakage - Check the fuel injection pump for leaks and fix it.
Fuel injectors are dirty or defective - Replace or clean fuel injectors.
Fuel injection pump is broken - Change or repair the pump.

Engine stalls during operation
Low coolant temperature - Warm up to required temperature.
Fuel filter is plugged - Clean or change the filter.
Air in the fuel system - Air bleeding.
Dirty or damaged injection nozzles - Inspect nozzles and replace if necessary.
Wrong setting of fuel injection pump timing - Set the fuel pump timing correctly.

Engine stops when idling
Low idle speed adjustment is incorrect - Correct low idle adjustment.
Fuel injection pump damage - Replace or repair injection pump.
Dirty or defective injectors - Change or clean fuel injectors.
Incorrect valve clearance - Need to adjust valve clearance.

Diesel engine loses power
Air cleaner is clogged - Install new air cleaner element.
Fuel injection nozzles are faulty or clogged - Inspect nozzles and replace if necessary.
Improper fuel injection pressure - Adjust to proper pressure.
Incorrect valve clearance - Check and adjust as required.
Too low idle RPM - Correct low idle settings.
Fuel hoses or lines are clogged - Fuel hoses and lines must be clean.
Cylinder head gasket is worn - Change cylinder head gasket.
Worn or broken piston rings - Change piston rings.

Engine overheated
Engine has a lack of coolant - Fill the cooling system and check components for leaks or other faults.
Insufficient engine oil - Checking oil level and add if necessary.
Damaged radiator cap or dirty radiator core - Clean radiator or replace cap.
Fan belt is worn or faulty - Replace as required.
Engine overload - Reduce load on the engine.

Oil pressure too low
Not enough oil in the engine - Fill up the engine oil.
Engine oil filter is plugged - Clean or replace engine oil filter element.
Incorrect engine oil Use proper viscosity oil.
Crankshaft bearing has excessive oil clearance - Replace bearings.
Oil pump malfunction - Remove and inspect oil pump.

Engine noises or knocks
Not enough engine oil - Check and refill engine oil.
Engine not warmed up - Warm up the engine.
Timing of fuel injection pump is incorrect - Set the fuel pump timing correctly.
Incorrect low idle setting - Correct low idle adjustment.
Damaged or clogged injectors - Clean fuel injectors or change it.
Connecting rod is worn or misaligned - Connecting rod needs to be aligned or changed.
Piston wear or scoring - Replace the pistons.

Drive System Troubleshooting

Drive system will not operate in either direction
Insufficient hydraulic oil - Check and refill the hydraulic oil.
Damaged or jammed undercarriage tracks - Repair or fix jamming.
Relief valve worn or defective - Change or repair relief valve.
Suction line or hydraulic filter is clogged - Service suction line or replace hydraulic filter.
Hand or foot controls malfunction - Check and repair as required.
Drive motor or pump is defective - Inspect and change as required.

Machine won't drive straight or drives jerkily
Jammed or damaged undercarriage tracks - Repair or fix jamming.
Tracks are sagging or faulty - Adjust track sag with tensioning or replace tracks.
Debris, dirt, or foreign objects stuck in undercarriage track frame - Clean track frame, remove debris and foreign objects.

Power is too low
Plugged hydraulic oil filter - Change hydraulic filter.
Relief valve is open or defective - Change or close relief valve.
Faulty or damaged transmission components - Inspect and replace defective parts.
Stuck input drive shaft - Service or change faulty drive shaft.
Air trapped in hydraulic system - Bleed hydraulic system.

Drive system overheats
Hydraulic fluid is insufficient - Fill the system to proper hydraulic fluid level.
Plugged hydraulic fluid filter - Replace or clean hydraulic filter.
Relief valve failure - Service or change relief valve.
Damaged drive pump or hydraulic motor - Repair or change faulty component.
Clogged hydraulic oil cooler - Clean the cooling fins.
Transmission overloading - Load should be reduced.

Drive system is excessively noisy
Improper oil viscosity - Use correct oil viscosity.
Hydraulic system is leaking air - Need to bleed air.
Defective drive pump or hydraulic motor - Repair or change faulty component.
Defective or worn mechanical components of drive system - Check drive system and change faulty parts.

Hydraulics Troubleshooting

Hydraulic system has overheating
Hydraulic pressure is incorrect - Correct adjustment is required.
Main relief valve failure or improper setting - Adjust or change relief valve.
Contaminated hydraulic fluid - The fluid must be changed.
Hydraulic oil level is insufficient - Add oil to the hydraulic system.
Hydraulic pump is faulty - Repair or replace pump if necessary.

Lift arm cannot be raised or lowered
Lift controls are defective - Inspect and repair if necessary.
Damaged hydraulic oil pump - Change or repair hydraulic pump if required.
Faulty hydraulic control valve - Change or repair hydraulic valve.
Hydraulic cylinder is faulty - Replace or repair boom cylinder.
Hydraulic fluid level low - Fill the system to proper hydraulic fluid level.

Bucket tilt does not work
Bucket controls are faulty - Repair or replace.
Hydraulic pump failure - Change or repair hydraulic pump if required.
Damaged hydraulic control valve - Repair or change the valve.
Broken bucket cylinder - Change or repair cylinder.
Hydraulic fluid is insufficient - Fill the system to proper hydraulic fluid level.

Slow bucket or lift arm operation
Defective hydraulic pump - Test the pump flow rate and install new pump if required.
Leaking hydraulic cylinder - Replace cylinder piston seals.
Low hydraulic oil level - Check and refill the hydraulic oil.
Worn or unadjusted hydraulic control valve - Set properly or repair.
Low hydraulic pressure - Hydraulic pressure must be set correctly.

Jerky operation of the bucket or boom
Air in hydraulic system - Air bleeding is required.
Hydraulic oil filter element is dirty - Clean or install new filter.
Hydraulic fluid is dirty - Change hydraulic fluid.
Cylinder tube or rod scoring - Replace worn component.

Hydraulic pump is noisy
Hydraulic leaks or low oil level - Top up hydraulic oil or remedy leakage in system.
Hydraulic filter is clogged - Replace or clean the filter.
Plugged suction line - Suction line needs to be cleaned.
Pump is sucking air - Bleed air from hydraulics.
Worn pump parts - Rebuild or install new pump.

Electrical Troubleshooting

Battery cannot be charged
Electrical wire connections are loose or corroded - Clean or tighten connections.
Faulty electrical terminal connectors - Replace terminal connectors.
Battery is worn - Battery replacement required.
Defective or loose belt - Need to adjust belt tension or replace belt.

Starter motor cranks slow
Battery voltage is low - Low battery charging, charge as required.
Battery does not hold charge - Service or change the battery.
Bad battery terminals or disconnected wiring - Check cables and clean or change terminals.

Starter motor is not working
Battery is discharged or worn - Battery needs to be recharged or replaced.
Disconnected or incorrectly connected wires - Inspect battery wires and connect correctly.
Battery voltage is low - Battery needs to be recharged.
Defective starter motor - Change or repair starter.