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322
80-160
Troubleshooting
BOOM LIFT CYLINDER
The suggested procedure for identifying the specific cause of leak-down should be performed in the
following sequence:
ELEVATE THE BOOM TO NEAR MAXIMUM ANGLE, not completely extended, with a boom length
sufficient to winch up a convenient payload approximately one (1) foot from ground level. Shut off
engine.
DISCONNECT THE EXTEND HOSE, PILOT DRAIN HOSE, AND THE SMALL PILOT LINE HOSE at the
holding valve ports and cap the pilot line hose and drain hose ends.
IF HYDRAULIC OIL CONTINUES TO RUN after the initial draining from either port of the hold valve as
the hoist cylinder continues to leak-down, the cause is within the hold valve.
IF CYLINDER LEAK-DOWN OCCURS with no oil leak from the hold valve ports, the cause is within the
cylinder.
OUTRIGGER JACK CYLINDER
The suggested procedure for identifying the specific cause of leak-down is similar to the boom lift
cylinder procedure:
SET THE OUTRIGGERS.
ELEVATE THE BOOM TO NEAR MAXIMUM ANGLE, not completely extended, with a boom length
sufficient to winch up a convenient payload approximately one (1) foot from ground level. Shut off engine
and remove pressure from the hydraulic reservoir by loosening the filler cap.
DISCONNECT THE EXTEND HOSE FROM THE HOLD VALVE. This is a hose farthest away from the port
tube and should have an “E” stamped next to it.
IF HYDRAULIC OIL CONTINUES TO RUN after the initial draining from the port of the hold valve as the
jack cylinder continues to leak-down, the cause is within the hold valve.
IF CYLINDER LEAK-DOWN OCCURS with no oil leak from the hold valve port, the cause is within the
cylinder.
DO NOT START THE ENGINE UNTIL THE HOSES HAVE BEEN RECONNECTED. The control valve spool
is open-center to reservoir in the neutral position and return line oil would be pumped out.