Removal and installation of fnr and nfpe modules, Charge relief valve, Shim adjustable charge relief valve components -27 – JLG 600SC_660SJC Service Manual User Manual
Page 287
SECTION 8 - HYDRAULICS
3121157
– JLG Lift –
8-27
Removal and Installation of FNR and NFPE
Modules
1.
Clean pump and module housings.
2.
Remove four (4) screws retaining module to housing
[4 mm Int. Hex], and remove module from pump
housing.
3.
Remove O-rings from the control ports. Examine
ports for cleanliness.
4.
Clean sealing surfaces.
5.
Replace locator pin.
6.
Install new O-rings.
7.
Replace screws [4.7-6.1 Nm (3.5-4.5 ft•lbf].
Removal and Installation of FNR and NFPE
Control Orifices
NOTE: Future models may contain an orifice plate between
module and pump housing. This will take the place
of the orifice plugs beneath the servo piston cover.
1.
Remove servo piston cover.
2.
Remove orifice plug [1/8 in Int. Hex].
3.
Examine orifice and port for cleanliness.
4.
Install orifice plug [2.0-3.4 Nm (1.5-2.5 ft•lbf)].
Charge Relief Valve
The charge relief valve may be removed for cleaning and
installation of fresh O-rings. The pressure setting may be
changed. However, note that the setting will vary for differ-
ent charge flows which depends on charge pump size
and pump speed. The factory setting is set relative to case
pressure at 1800 rpm. The actual charge pressure will
vary at different speeds.
SHIM ADJUSTABLE STYLE
1.
Remove the shim adjustable charge relief valve plug
[1 in Hex] from the pump housing. Remove the O-
ring from the plug.
2.
Remove the spring and poppet from the housing.
3.
Do not alter the shims which may be installed
between the spring and valve plug, or interchange
parts with another valve. Inspect the poppet and
mating seat in the housing for damage or foreign
material.
4.
If desired, the charge relief valve setting can be
changed. An approximate rule of thumb is 4 bar /
1.25 mm (58 psi / 0.050 in). The effective setting will
vary.
To confirm the charge relief valve setting, measure
charge pressure (port M3) with the pump in stroke.
The charge pressure should level off when the relief
setting is reached.
1. Plug
2. O-ring
3. Shims
4. Spring T-Seal
5. Poppet
Figure 8-22. Shim Adjustable Charge Relief Valve
Components