SkyTrak 8042 Service Manual - Manual (Page 578)

8.163 Model 8042, 10042, 10054 Legacy Rev. 10/03
Hydraulic System
7. Install a new piston square seal (10), square ring
(11) and precision wearband (12) onto the piston (7).
8. Apply Loctite Primer “T” and Threadlocker #271
(red) to the threads of the piston (7) in accordance
with Loctite instructions. Thread the piston (7) onto
the rod (4) and torque to 440-500 ft-lb (597-678 Nm).
9. Install two new setscrews (8) with locking inserts (9)
into their holes in the piston (7). Torque to 85-95 lb-ft
(115-124 Nm).
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 (6).
10. Place the cylinder tube (6) in a soft-jawed vise or
other acceptable holding equipment if possible.
11. Lubricate the piston (7), head gland (5) and the
inside of the tube (6) with clean, filtered hydraulic oil.
12. Apply a compression sleeve or other suitable tool to
the head gland (5) in order to compress the o-rings
(15 and 17).
IMPORTANT: When sliding the rod and piston assembly
in the tube, prevent the threaded end of the tube from
damaging the piston (7). Keep the rod centered within
the tube to help prevent binding.
13. Carefully insert the rod (4) with all attachments
straight into the tube (6). Use a pin spanner wrench
to thread the head gland into the tube. Torque the
head gland to 250-300 lb-ft (339-407 Nm). Remove
the compression tool.
14. Using new oiled o-rings, install the counterbalance
valve (2) and direct-acting relief valve (3). Lubricate
the cartridge and valve with clean, filtered hydraulic
oil. Torque the valves to 35-40 lb-ft (47-54 Nm).
15. Test the cylinder at low operating pressure (100 psi
or 7 bar). Verify that the piston and rod move freely
in both directions.
16. Increase the operating pressure to the maximum for
the cylinder (3000 psi or 207 bar). Verify that the
piston and rod move freely in both directions.
17. Retract the piston fully and cap the hydraulic hose
ports. Install the cylinder on the carriage.
18. If the bearing (22) requires replacement, support the
rod (4) in a soft-jawed vise or other suitable holding
device. Carefully press a new bearing into the rod
eyelet.
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