JLG G5-18A Service Manual page 154

Hydraulic System
b. Pilot Select Valve Disassembly, Cleaning,
Inspection and Assembly
1. Place the pilot select assembly on a suitable work
surface.
2. Remove the solenoid valves and cartridges from the
steer select housing.
3. Clean all components with a suitable cleaner before
inspection.
4. 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.
5. Inspect internal passageways of the steer select
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 unit
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.
6. Install the solenoid valves and cartridges in the pilot
select housing.
c. Pilot Select Valve Installation
1. Attach the pilot select manifold valve to the mounting
plate on the frame using the socket head capscrews.
2. Connect the hydraulic hoses, fittings, solenoid wire
terminal leads, etc., to the pilot select valve.
3. Check the routing of all hoses, wiring and tubing for
sharp bends or interference with any rotating
members, and install tie wraps and/or protective
conduit as required. Tighten all tube and hose clamps.
8-18
2
4. Start the engine and run at approximately 1/3-1/2
throttle for about one minute, without moving the
machine or operating any hydraulic functions.
5. Inspect for leaks and check the level of the hydraulic
fluid in the reservoir. Shut the engine OFF.
Note: Check for leaks and repair as required before
continuing. Add hydraulic fluid to the reservoir as needed.
6. Wipe up any hydraulic fluid spillage in, on, near and
around the machine, work area and tools.
7. Close and secure the engine cover.
d. Joystick Test
1. Conduct a function test of the joystick. Refer to
Section 8.6, "Hydraulic Schematics," or Section 9.4,
"Electrical System Schematics," for details.
2. Check boom lift/lower (2), auxiliary (3) and tilt (4) for
proper function.
8.10.7 Inching Valve
The inching valve is attached at the front of the frame
directly above the steer select valve.
Verify the correct operation of the inching valve solenoid
before considering replacement of the valve. The housing
of the inching valve is not serviceable and must be
replaced if defective.
a. Inching Valve Removal
1. Park the machine on a firm, level surface, fully
retract the boom, lower the boom, place the
transmission control lever in (N) NEUTRAL, engage
the park brake and shut the engine OFF.
2. Place an Do Not Operate Tag on both the ignition
key switch and the steering wheel, stating that the
machine should not be operated.
3
4
MY2170
G5-18A, 2505