JLG 600SC_660SJC Service Manual - Manual (Page 187)

SECTION 5 - HYDRAULICS
3121607 – JLG Lift – 5-43
5. Install new O-ring on valve plug. Reinstall poppet,
spring, and plug (with shims and O-ring) into pump
housing. Torque to 40-100 ft-lb (55-135 Nm).
SCREW ADJUSTABLE STYLE
1. Mark plug, lock nut, and housing to maintain original
adjustment before removing screw adjustable relief valve
plug. Loosen lock nut (1-1/16" Hex) and remove plug (8
mm Int. Hex). Remove O-ring from plug.
2. Remove spring and poppet from housing.
3. Inspect poppet and mating seat in housing for damage
or foreign material.
4. Install new O-ring on valve plug. Reinstall poppet and
spring. Reinstall plug and lock nut. Torque to 34 - 42 ft-lb
(47-57 Nm), aligning marks made at disassembly.
5. Check and adjust charge pressure if necessary. For screw
adjustable “anti-stall” charge relief valves, an approxi-
mate rule of thumb is 2.8 bar/quarter turn (40 psi/quar-
ter turn).
6. Measure charge pressure (port M3) with pump in stroke.
Charge pressure should level off when relief setting is
reached.
Shaft Seal and Shaft Replacement
A lip type shaft seal is used in Series 42 pumps. Seal and shaft
can be replaced without major unit disassembly. Replacement
generally requires removing pump from machine.
1. Lock Nut
2. O-Ring
3. Plug
4. Spring T-Seal
5. Poppet
Figure 5-71. Screw Adjustable Charge Relief Valve
Components
1. Retaining Ring 2. Seal Carrier Assembly
Figure 5-72. Shaft Seal Components
1. O-Ring
2. Seal
3. Seal Carrier
4. Sealant may be used on outside diameter
5. Inside Lip (face down)
6. Press Seal to Bottom of Seal Carrier
Figure 5-73. Installation of Shaft Seal