Terex RT700 - Boom Lift Cylinder Leakage Procedures; Outrigger Jack Cylinder Leakage Procedures; Excessive Oil Heating Troubleshooting

TROUBLESHOOTING
BOOM LIFT CYLINDER (CONTINUED)
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 cylin-
der 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 ini-
tial draining from the port of the hold valve as the jack cylin-
der 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.
HEATING CAUSED BY POWER UNIT
(RESERVOIR, PUMP, RELIEF VALVE, AND COOLERS)
CAUSE REMEDY
Relief valve set at a higher or lower pressure than
specified. Excess oil dissipated through increased
slippage in various parts, or through relief valve..................................Reset relief valve to recommended pressure.
Internal oil leakage due to wear ............................................................Repair or replace faulty component.
Viscosity of oil too high or too low.......................................................Follow recommendations for correct viscosity grade
to be used.
Pumps assembled after overhaul may be assembled
too tightly. This reduces clearances and increases
rubbing friction......................................................................................Follow instructions when reassembling.
EXCESSIVE HEATING OF OIL
IN SYSTEM
RT700 Series Page 5 - 30 Issued: August 2003