GUIDE 0947748 - Caterpillar

Troubleshooting the Auxiliary Hydraulic System
Problem List
"The Auxiliary Pump Has Excessive Noise"
"The Auxiliary Pump is Overheating"
"The Hydraulic Oil is Overheating"
"The Hydraulic System Does Not Contain Any Hydraulic Pressure"
"The Hydraulic System Does Not Have Any Oil Flow"
"The Hydraulic Oil Pressure Fluctuates"
"The Machine has a Sluggish Response"
"The Machine is Experiencing an Erratic Grade Control Problem"
"There is a Large Amount of Air in the System"Problems and Probable Causes
The Auxiliary Pump Has Excessive Noise
Probable Cause
The auxiliary pump is cavitating.
There is air in the hydraulic oil or supply lines.
The auxiliary pump has been damaged.The Auxiliary Pump is Overheating
Probable Cause
The hydraulic oil overheated.
The auxiliary pump is cavitating.
There is air in the hydraulic oil or the supply lines.
The auxiliary pump has been damaged.The Hydraulic Oil is Overheating
Probable Cause
The oil level in the hydraulic tank is too low.
The hydraulic pressure is too low or the pressure is too high.
The return oil filter is clogged.
There is a faulty bypass valve in another system.
There is a restriction of the flow of oil through the oil cooler.
There is a faulty motor in another system.
There is a restriction in a hydraulic oil line.
There is an excessive load on one or more systems.
The wrong type of hydraulic oil was used.
The auxiliary pump is damaged.The Hydraulic System Does Not Contain Any Hydraulic Pressure
Probable Cause
The hydraulic system does not contain any oil flow.The Hydraulic System Does Not Have Any Oil Flow
Probable Cause
The auxiliary pump is not receiving any oil.
The auxiliary pump is faulty.
The hydraulic oil level is low.
The hydraulic supply lines are restricted.
The hydraulic system is leaking.
The components are leaking.The Hydraulic Oil Pressure Fluctuates
Probable Cause
The hydraulic system contains trapped air.
The hydraulic oil is contaminated.
The auxiliary pump is faulty.The Machine has a Sluggish Response
The pressure compensator was set improperly.
There is a blockage in the suction strainer on the hydraulic tank.
There is a blockage in the oil filter or return filter.
There is a faulty control valve.
The setting for displacement limiter is set to low.
There is an excessive load on one or more systems.
There is a faulty pump.
The wrong type of hydraulic oil was used.
The hydraulic oil is not up to operating temperature.
There is a fault in the electrical circuit.The Machine is Experiencing an Erratic Grade Control Problem
The grade controls were set incorrectly. Refer to the Operation and Maintenance Manual for the grade control on your machine.Refer to the Operation and Maintenance Manual for your machine.
There is a fault in the electrical circuit.Troubleshooting the Hydraulic Cylinders for the Auxiliary Hydraulic System
Problem List
"The Hydraulic Cylinders will not Operate or Have a Sluggish Response"Problems and Probable Causes
The Hydraulic Cylinders will not Operate or Have a Sluggish Response
Refer to the corresponding screed manual for the location of the screed components. Consult your Caterpillar Dealer for replacement manuals.Note: Refer to the Operation and Maintenance Manual for your machine.
The hydraulic cylinders should be checked for damage on a regular basis. There are hydraulic cylinders on the machine and the screed.
The wiper seal that is installed on the cylinder rod prevents dirt from entering the hydraulic cylinder. Dirt can pass by the wiper