AXLE AR-FIXED 1178251 - Caterpillar

Do not check for leaks with your hands. Pin hole (very small) leaks can result in a high velocity oil stream that will be invisible close to the hose. This oil could penetrate the skin and cause personal injury. Use cardboard or paper to locate pin hole leaks.
Visual Checks
A visual inspection of the hydraulic system and its components is the first step when a diagnosis of a problem is made. Make the inspection with the engine off and the parking brake engaged.1. Check the oil level in the hydraulic tank.2. Remove the filter element and check it for material that would give an indication of damage to a component.3. Inspect all lines and connections for damage or leaks.4. Inspect all controls for damaged components.Checks During Operation
The checks during operation can be used to find a valve or pump that is not working correctly. The torque on a motor can be used to check the condition of the motor and the pump.1. Listen for noise from the pump.2. Listen for the sound of the relief valves when they open. Relief pressures that are too low will cause reduced force of all functions and will cause an increase in the operating cycle time of the functions. Opening pressures that are too high will cause a decrease in the service life of hoses, components and structures. Problem 1: Pump excessively noisy. Probable Cause:* Pump cavitating.* Oil too thick.* Ambient temperature too low.* Air in hydraulic oil.* Pump worn or damaged. Problem 2: Pump excessively hot. Probable Cause:* Hydraulic oil overheated.* Internal leakage.* Oil cooler plugged.* Pump cavitating.* Air in hydraulic oil.* Excessive load.* Pump worn or damaged. Problem 3: Hydraulic oil overheated. Probable Cause:* System pressure too high.* Fluid dirty or level low.* Incorrect fluid viscosity.* Hydraulic oil cooler plugged or dirty.* Pump worn or damaged. Problem 4: No hydraulic oil pressure. Probable Cause:* No hydraulic oil flow. Problem 5: No hydraulic oil flow. Probable Cause:* EDC failure.* Hydraulic pump not receiving fluid.* Pump damaged.* Pump improperly assembled.* Low hydraulic fluid.* Plugged hydraulic line. Problem 6: Low hydraulic oil flow. Probable Cause:* Loose fittings.* External leak in hydraulic system.* Leaking gaskets or seals in pump.* Pump worn. Problem 7: Erratic hydraulic oil pressure. Probable Cause:* Air in hydraulic oil.* Hydraulic oil contaminated.* Pump worn. Problem 8: Air compressor runs hot. Probable Cause:* Dirty air intake filter.* Crankcase oil level low. Problem 9: Air compressor runs slow or does not run. Probable Cause:* Hydraulic pump worn.* Hydraulic motor worn. Problem 10: Air compressor will not stop running. Probable Cause:* Air pressure switch set wrong.* Leak in hoses or fittings. Problem 11: Air pressure too low. Probable Cause:* Air pressure switch set wrong.* Leak in hoses or fittings.* Air pressure switch set wrong.* Leak in hoses or fittings. Problem 12: Air pressure too high. Probable Cause:* Air pressure switch set wrong.System Tests And Adjustments
Relief Valve Pressure Test
Make reference to on the first page of Troubleshooting.
1. Make sure the parking brake is applied, and