JLG 660SJ Service Manual - Manual (Page 237)

SECTION 5 - HYDRAULICS
3121202 – JLG Lift – 5-27
The appropriate check valve kit and/ or check and
relief valve kit should be used. Refer to appropriate
Service Parts Manual.
NOTE: Always replace ball type charge check valves with
the poppet type.
4. Reinstall the valve cartridge, spring, and plug (with
O-ring) into the housing. Torque the plug to 30 to 70
ft. lbs. (41 to 95 Nm).
THE RELIEF VALVES ARE FACTORY SET AND SHOULD NOT BE
TAMPERED WITH EXCEPT FOR REPLACING THE ENTIRE CAR-
TRIDGE. DISASSEMBLY MAY CHANGE THE SETTING AND CAUSE
ERRATIC UNIT OPERATION OR PREMATURE FAILURE.
CHARGE PRESSURE RELIEF VALVE
1. Remove charge relief valve hex plug.
2. Remove the spring and poppet from the housing.
Do not alter the shims or interchange parts with
another valve. Inspect the poppet and mating seat in
the end cap for damage or foreign material.
3. Reinstall the poppet, spring, and plug (with shims
and O-ring) into the housing. Torque the plug to 30
to 70 ft. lbs.(41 to 95 Nm).
ELECTRICAL DISPLACEMENT CONTROLS (EDC)
THE REMOVAL OF ANY PORTION OF THE CONTROL MECHANISM
MAY RESULT IN LOSS OF NEUTRAL, WHICH WILL NECESSITATE
READJUSTMENT.
1. Remove the four control mounting screws using an
internal hex wrench (3/16”).
2. Carefully lift the control off the pump housing.