JLG sky trak mmv Service Manual page 454

Hydraulic System
11
13
WARNING:
under pressure can penetrate the skin, causing
death or serious injury. Relieve hydraulic pres-
sure before servicing any hydraulic component.
4. Label or otherwise mark the lift/lower cylinder
hydraulic hoses. Disconnect and cap all hoses and
fittings.
5. Attach a sling to the lift/lower cylinder and to a hoist
or an overhead crane. Support the lift/lower cylinder
in the sling, and remove the nuts, capscrews and
cylinder mount pins from the cylinder. The lower
cylinder mounting pin is held in place with a retainer
clevis pin and hair pin.
6. Safely and carefully, remove the lift/lower cylinder
from the vehicle. Wipe up any hydraulic fluid spillage
in, on, near and around the vehicle.
9.156
1
26
24
23
19
16
15
28
17
18
14
Escaping hydraulic fluid
10
9
8
10
12
25
21
22
12
27
3
5
4
b. Lift/Lower Cylinder Disassembly
Note: An additional o-ring may be included at the base
of the cylinder rod. This additional o-ring may be dis-
carded, as it served only in a temporarily protective role.
1. Clean the lift/lower cylinder (1) with a suitable
cleaner. Remove all dirt, debris and grease from the
cylinder.
IMPORTANT: Avoid using excess force when clamping
the cylinder in a vise. Apply only enough force to hold the
cylinder securely. Excessive force can damage the cylin-
der tube (2).
2. Secure the lift/lower cylinder in a soft-jawed vise or
other acceptable holding equipment if possible.
WARNING:
be trapped inside the cylinder. Exercise caution
when removing a counterbalance valve or a pilot-
operated check valve from a cylinder. Escaping
hydraulic fluid under pressure can penetrate the
skin, causing death or serious injury.
12
11
1
29
2
3
4
5
7
6
8
20
2
6
Significant pressure may
Model MMV Rev. 12/04
7 9
MT2801