SPRING 5254282 - Caterpillar

Checks During Operation
The checks during operation can be used to find a valve or a pump that is not working correctly. The speed of the rod movement or the torque on a motor can be used to check the condition of the cylinders, the motors and the pumps.
Feel the cylinders as the cylinders extend and the cylinders retract. Movement must be smooth and regular.
Listen for noise from the pumps.
Listen for the sound of the relief valves when the relief valves open. Relief pressures that are too low will cause reduced force of all functions. This will cause an increase in oil temperatures and in the operating cycle time of the components.Note: Operating pressures that are too high will cause a decrease in the service life of hoses, components and structures.
Be aware of the drift rate in the machine functions that are caused by cylinder leakage, control valve o-rings or improperly seated valves. A poor adjustment or a poor fit in the pilot control valve or the main control valve could also cause drift.Hydraulic Pump Troubleshooting
Note: The problem is a pump that is excessively noisy.The probable cause may be listed below.
Pump cavitating.
Air is in the hydraulic oil.
The pump is worn or damaged.The problem is a pump that is excessively hot.The probable cause may be listed below.
Hydraulic oil overheated.
The pump is cavitating.
Air is in the hydraulic oil.
There is an excessive load.
The pump is worn or damaged.The problem is the hydraulic oil that is overheated.The probable cause may be listed below.
System pressure is too high.
Fluid is dirty or the level is low.
The fluid viscosity is incorrect.
The hydraulic oil cooler is plugged or dirty.
The pump is worn or damaged.The problem is a machine system that has no hydraulic oil pressure.The probable cause may be listed below.
There is no hydraulic oil flow.The problem is a machine system that has no hydraulic oil flow.The probable cause may be listed below.
The hydraulic pump is not receiving fluid.
The pump is damaged.
The pump is improperly assembled.
The hydraulic fluid is low.
The hydraulic line is plugged.The problem is a low hydraulic oil flow.The probable cause may be listed below.
There is an external leak in the hydraulic system.
The pump is worn.The problem is a hydraulic oil pressure that is erratic.The probable cause may be listed below.
There is air in the hydraulic oil.
The hydraulic oil is contaminated.
The pump is worn.