JLG sky trak mmv Service Manual page 432

Hydraulic System
b. Fork Side Shift Valve and Manifold Disassembly,
Cleaning, Inspection and Assembly
1. Place the fork side shift valve and manifold assembly
on a suitable work surface.
2. Remove the fork side shift valve assemblies (1) from
the manifold (2) by removing the four socket head
capscrews (3) from each valve. Discard the four o-
rings (4) under each valve. Retain the "P" port orifice
disks (5) from the underside of each shift valve
housing (6).
3. Remove the solenoid coils and cartridges (7) from
each end of the fork side shift valves (1).
4. Clean all components with a suitable cleaner before
inspection.
5. Inspect the solenoid cartridges for proper operation.
Check by shifting the spool to ensure that it is
functioning properly. Check that the spring is intact.
Inspect the cartridge interior for contamination.
7
5
4
6
3
3
7
1
9.134
7
5
4
6
7
1
6. Inspect internal passageways of the fork side shift
manifold and valve for wear, damage, etc. If inner
surfaces of the manifold DO NOT display an ultra-
smooth, polished finish, or components are
damaged in any way, replace the manifold or
appropriate part. Often, dirty hydraulic fluid causes
failure of internal seals and damage to the polished
surfaces within the side shift manifold.
Note: ALWAYS replace seals, o-rings, gaskets, etc.,
with new parts to help ensure proper sealing and opera-
tion. Lubricate seals and o-rings with clean hydraulic oil.
7. Install the solenoid valve cartridges and coils (7) in
the fork side shift valve housing (6).
8. Attach each fork side shift valve assembly (1) to the
manifold (2) using four new oiled o-rings (4) under
each valve. Be sure the orifice disks (5) are in place
under each side shift valve assembly. Secure in
place using four socket head capscrews (3) for each
valve.
2
MM3761
Model MMV Rev. 12/04