SkyTrak 8042 Service Manual - Manual (Page 539)

Hydraulic System
8.124 Model 8042, 10042, 10054 Legacy Rev. 10/03
6. Attach a suitable sling to an overhead crane or other
suitable device and to the extend/retract cylinder.
Make sure the device used can actually support the
cylinder.
7. Remove the two 2" external retaining rings securing
the extend/retract cylinder rod pin to the
intermediate boom section. Remove the pin.
8. Remove the two 2" external retaining rings securing
the extend/retract cylinder base pin to the outer
boom. Remove the pin.
9. Remove the extend/retract cylinder from the vehicle.
Wipe up any hydraulic fluid spillage in, on, near or
around the vehicle.
b. Extend/Retract Cylinder Disassembly
Note: An additional o-ring may be included at the base
of the cylinder rod. This additional o-ring may be discarded,
as it served only in a temporarily protective role.
1. Clean the extend/retract 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
cylinder tube (2).
2. Secure the extend/retract cylinder in a soft-jawed
vise, or other acceptable holding equipment if possible.
3. Slowly remove the counterbalance valve (3) and the
pilot-operated check valve (4).
IMPORTANT: DO NOT tamper with or attempt to reset
the counterbalance valve cartridge. If adjustment or
replacement is necessary, replace a counterbalance
valve with a new part.
4. Extend the rod (5) as required to allow access to the
base of the cylinder.
IMPORTANT: Protect the finish on the rod at all times.
Damage to the surface of the rod can cause seal failure.
MH2880
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WARNING:
Significant pressure may 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.