JLG G5-18A Service Manual User Manual
Page 115
8-25
G5-18A, 2505H, 25.5
Hydraulic System
4. Inspect the solenoid cartridge 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 variable speed
fan 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 valve and cartridge in the variable
speed fan valve housing.
c. Variable Speed Fan Valve Installation
1. Connect the hydraulic hoses, fittings, solenoid wire
terminal leads, etc., to the variable fan valve.
2. Refer to Section 7.2.2, “Radiator/Oil Cooler
Replacement,” for detailed installation instructions.
3. Properly connect the battery.
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 battery and engine covers.
8. Remove the Do Not Operate Tags from both the
ignition key and the steering wheel.
d. Variable Speed Fan Valve Test
1. Turn the ignition switch to the ON position, activate
the variable speed fan switch to the ON position.
2. Place a piece of paper over the face of the radiator
core. If the paper is held in place, the fan is rotating
in the right direction.
3. If further troubleshooting is required, refer to Section
8.7, “Hydraulic Schematic,” or Section 9.4, “Electrical
System Schematics.”