SkyTrak 6042 Service Manual - Manual (Page 340)

Hydraulic System
8.108 Model 6042 Legacy Origin 7/02
Figure 8-72 Extend/Retract Cylinder Components
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 (Fig. 8 -72, 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 (Fig. 8-72, 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 (Fig. 8-72, 3)
with tamper proof cap (4) and the pilot-operated check
valve (5) from the block manifold.
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 (Fig. 8-72, 6) 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.
1
2
3
4
5
6
7
8
9
10
11
12
18
19
16
17
20
Torque to
300-400 lb-ft
(407-542 Nm)
Apply Loctite
#271 to threads
and torque to
330-390 lb-ft
(448-529 Nm)
24
22
Apply Loctite #243 to
threads and torque to
10-12 lb-ft (14-16 Nm)
21
23
28
27
Torque to
40-50 lb-ft
(54-68 Nm)
26
25
14
15
13
29
30
Apply Loctite #243 to
threads and torque to
10-26 lb-ft (14-35 Nm)
13
16
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. Escap-
ing hydraulic fluid under pressure can pene-
trate the skin, causing death or serious injury.