JLG 340AJ Service Manual - Manual (Page 205)

SECTION 5 - HYDRAULICS
3121259 – JLG Lift – 5-47
HPRV VALVE
HPRV valves are available as complete units only. If you sus-
pect valve malfunction, replace the valve(s) and test pump
operation. Replace O-rings before reassembly.
OPTIONAL DISPLACEMENT LIMITER
Inspect the displacement limiter screw threads. Ensure that
the screw is not bent. Replace the seal/nut.
CHARGE PRESSURE RELIEF VALVE
Charge pressure relief valve is available as a complete unit
only. If you suspect valve malfunction, replace the valve and
test pump operation. Replace O-rings before assembly.
SERVO PISTON ASSEMBLY
NOTE: Do not disassemble servo piston assembly. Replacement
servo piston assembly is available as a complete unit only.
Inspect slider block for wear or damage. Replace if necessary.
Inspect springs for warping or cracking. Replace entire assem-
bly if springs are damaged. Inspect servo piston for wear,
cracks, or damage. Replace entire assembly if servo piston is
damaged.
CONTROL
NOTE: If you suspect a coil malfunction, remove the coil by remov-
ing the plastic nut with a 26 mm 12 point socket. Install a
new coil. Torque nut to 5 Nm [3.7 ft.Ibs.].
Inspect sealing sur faces of control. If you find nicks or
scratches that may allow fluid leakage, replace control. Inspect
feedback spring and linkage. Control is available as a complete
unit only. If you suspect control operation problems, replace
control with a new unit and test pump. If necessary, you may
remove and clean the control orifices. Use a 3 mm internal hex.
wrench Torque to 2.5 Nm [1.8 Ib.ft.]. Remove and replace the
screen if contaminated. Screen is not serviceable.