JLG 3507 Service Manual page 90

Hydraulic System
9. Support the valve and remove the four bolts securing
the main control valve bracket to the frame.
10. Remove the main control valve and bracket from the
frame and remove the four bolts holding the
mounting bracket to the valve.
b. Main Control Valve Disassembly
1. To disassemble the individual sections of the main
control valve, remove the nuts and from the end of
the tie rod. Pull the tie rods out through the sections.
2. Disassemble each section assembly as required.
Some sections include a pre-adjusted relief valve that
regulates pressure in a specific circuit.
IMPORTANT: DO NOT adjust any of the relief valve
assemblies! Tampering with a relief valve will irrevocably
alter pressure in the affected circuit, requiring recalibration
or a new relief valve.
VALVE SECTION
INLET MODULE
Disassemble each Valve Section
1. Carefully separate the load sense outlet section from the
extend/retract section.
2. Remove the o-rings from between the two sections.
3. Carefully separate each remaining section being
careful not to lose the load sense shuttle ball.
4. Remove both end caps from each end of the valve
sections then remove each control spool.
5. Remove any check valves, compensator valves,
anti-cavitation valves or shock valves from each
individual valve section if equipped.
6. Keep all parts being removed from individual valve
sections tagged and kept together.
c. Main Control Valve Parts Cleaning
Clean all components with a suitable cleaner, such as
trichlorethylene, before continuing. Blow dry.
8.12
d. Main Control Valve Parts Inspection
Inspect all parts and internal passageways for wear,
damage, etc. If inner surfaces of any component DO NOT
display an ultra-smooth, polished finish, or are damaged
in any way, replace the damaged part. Often, dirty
hydraulic fluid causes failure of internal seals, damage to
the polished surfaces within the component, and wear of
and/or harm to other parts.
e. Main Control Valve Assembly
Note: ALWAYS replace seals, o-rings, gaskets, etc.,
with new parts to help ensure proper sealing and
operation. Lubricate seals and o-rings with clean
hydraulic oil.
Assemble each Valve Section
1. Reassemble any check valves, compensator valves,
anti-cavitation valves or shock valves from individual
valve sections if equipped.
2. Install the control spool being careful not to nick or
END SECTION
scratch the valve section bore or the control spool.
3. Install the end caps on each end of the valve section.
Assemble the Main Control Valve.
1. Place all three tie rods with the washers and nuts
through the end main control valve section.
2. Stand the end main control valve section on end.
3. Install proper o-rings and load sense shuttle on the
inner face of the end main control valve section.
MZ1500
Align the extend/retract section over the three tie
rods and slide onto the end main control valve
section.
4. Using proper o-rings and load sense shuttle, repeat
step three for the remaining sections.
5. Install the washers and nuts on the tie rods and
torque to 22 Nm (195 lb-in).
f. Main Control Valve Installation
1. Loosely install the four main control valve mounting
bolts through bracket on the inside rail of the engine
bay.
2. Install the main control valve onto the bracket,
aligning the bolts with the holes in the end sections
of the main control valve. Slide the main control
valve into position, and tighten the bolts.
3. Prime the main control valve by filling the inlet
openings with fresh, filtered hydraulic oil from a
clean container, before attaching the hoses.
3507, 3508, 3509, 3512, 3513, 4007, 4008, 4009, 4012, 4013
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