JLG G12-55A Service Manual - Manual (Page 131)

8-11 G10-55A, G12-55A
Hydraulic System
c. Cleaning and Drying
If contaminated hydraulic oil or foreign material is in the
tank, the tank can usually be cleaned.
Note: If a leak is suspected in the hydraulic oil reservoir,
contact your local JLG distributor.
To clean the hydraulic oil reservoir:
1. Have a dry chemical (Class B) fire extinguisher near
the work area.
2. Remove the hydraulic oil reservoir drain plug, and
safely drain any hydraulic oil into a suitable
container. Dispose of hydraulic oil properly.
3. Clean the hydraulic oil reservoir with a high-pressure
washer, or flush the tank with hot water for five
minutes and drain the water. Dispose of
contaminated water properly.
d. Inspection
1. Inspect the hydraulic oil reservoir thoroughly for any
cracks, slices, leaks or other damage.
2. With hydraulic oil reservoir removed from machine,
plug all openings except one elbow fitting. Install
elbow fitting, and apply approximately 1-1.5 psi (7-10
kPa) of air pressure through elbow. Check reservoir
for leaks by applying a soap solution to exterior
and look for bubbles to appear at the cracked or
damaged area.
e. Reservoir Installation
1. Place hydraulic oil reservoir into original orientation.
2. Secure hydraulic oil reservoir to frame with previous
mounting hardware.
3. Uncap and connect the previously labeled hydraulic
hoses to their appropriate locations.
4. Install the hydraulic fluid level sight-glass using
special designed and drilled capscrews and gaskets.
5. Install hydraulic filter bracket and hydraulic filter.
6. Fill the hydraulic oil reservoir according to
specifications. Refer to Section 2.5, “Fluid and
Lubricant Capacities.”
7. Check the hydraulic oil reservoir for leaks.
8. Properly connect the batteries.
9. Close and secure the engine cover.
10. Remove the Do Not Operate Tags from both the
ignition key switch and the steering wheel.
8.6 IMPLEMENT PUMP
For internal service instructions, contact your local
JLG distributor.
8.6.1 Implement Pump Replacement
a. Pump Removal
1. Park machine on a firm, level surface, level machine,
fully retract boom, lower boom, place transmission
control lever in (N) NEUTRAL, engage park brake and
shut engine OFF.
2. Place a Do Not Operate Tag on both the ignition key
switch and the steering wheel.
3. Open engine cover. Allow system fluids to cool.
4. Properly disconnect the batteries.
5. Drain the hydraulic reservoir. Refer to Section 8.5.1,
“Hydraulic Oil Reservoir Draining.”
6. Thoroughly clean the pump and surrounding area,
including all hoses and fittings before proceeding.
Note: Cap all hoses as you remove them to prevent
unnecessary fluid spillage.
7. Label, disconnect and cap the hydraulic hoses
attached to the pump.
8. Remove the four bolts and lockwashers (2) securing
the pump to the transmission (top bolts shown only).
Remove the o-ring located between the transmission
and the pump. Wipe up any hydraulic oil spillage.
MY7110
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