Maintenance & Repair
25
Compressor Hydraulic Oil Change
Check the oil in the hydraulic reservoir quarterly, and replace the oil on an annual basis.
Purging the system requires a new oil supply sufficient to completely fill the reservoir, lines,
cylinders, etc., and an extra quantity for loss during this procedure. To minimize oil loss during
this process, operate the truck engine at low RPM.
Two operators are required during the purging operation: one to operate the compressor and the
other to regulate pump flow (engine speed).
CAUTION
DO NOT ALLOW THE RESERVOIR OIL LEVEL TO DROP BELOW 1/3 CAPACITY DURING
THIS OPERATION.
1
Drain the hydraulic oil reservoir. Disconnect the suction hose to the pump, drain and
reassemble. Change the suction filter cartridge.
NOTE
DISPOSE OF WASTE OIL IN A RESPONSIBLE MANNER, FOLLOWING ANY FEDERAL,
STATE, OR LOCAL REGULATIONS.
2
Remove the reservoir return line. Direct flow into a sump or waste container. Plug the drain
port on the reservoir and fill with new oil.
NOTE
READ AND FOLLOW THE FOLLOWING INSTRUCTIONS WITHOUT INTERRUPTION OR
STOP THE ENGINE AT THE END OF EACH STEP. IF THIS IS NOT DONE, EXCESS OIL
WASTE WILL BE DISCHARGED.
3
Start the truck engine and engage the PTO. Slowly release the clutch. Activate the control
valve so that the fluid passes through the motor. Allow fluid to discharge for about 15
seconds. Kill the engine.
4
Reconnect the return line to the reservoir port. Change the return line filter. All components
of the system are now purged.
5
Check hydraulic oil level. Top off if necessary.
