Lull 944E-42 Service Manual - Manual (Page 485)

8.233 Model 644E-42/944E-42 Rev. 6/04
Hydraulic System
11. Apply Loctite Primer “T” and Threadlocker #271
(red), to a new locknut (7) in accordance with Loctite
instructions. Install the nut onto the threaded end of
the rod (6). Torque the nut to 1840-2025 lb-ft
(2495-2745 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 (5).
12. Fasten the tube (5) in a soft-jawed vise or other
suitable holding device.
13. To aid in installation, lubricate the o-rings and the
inside of the tube, piston and head gland with clean,
filtered hydraulic oil.
IMPORTANT: Use a suitable installation tool or
compression sleeve to help prevent twisting or damaging
the seals and o-rings when installing the piston (8) and
head gland (4) into the cylinder. When sliding the rod
and piston assembly in the tube, DO NOT damage the
piston by scraping it against the threads in the tube.
Keep the rod in line with the tube to prevent binding.
14. Keep the rod (6) straight and carefully insert the rod
into the tube (5). Avoid scratching, nicking or
damaging the tube while installing the rod.
15. Begin threading the head gland (4) into the tube (5).
Place the locking insert (3) in its hole in the head
gland threads just before the head gland is threaded
into the tube. Use a suitable pin spanner wrench to
thread the head gland (4) completely into the
tube (5). Torque the head gland to 300-400 lb-ft
(407-542 Nm).
16. Lubricate the pilot-operated check valves (2) with
clean, filtered hydraulic oil. Using all new seals,
thread the pilot-operated check valves into tube (5).
Torque valves to 35-40 lb-ft (47,2-54,2 Nm). Refer to
the Parts Manual for seal kits.
17. Press the polylube bearings (21) into the base end
of the cylinder tube.
18. Reinstall the two hex plugs (22). Apply Loctite
Threadlocker #243 to the threads and torque to 10-
12 lb-ft (14-16 Nm).
19. Test the cylinder at low operating pressure
(100 psi or 6,9 bar) to verify that the piston and rod
move freely in both directions.
20. Increase the operating pressure to the maximum for
the cylinder (4000 psi or 275 bar) and check for external
leakage and for free movement in both directions.
21. Retract the piston fully.
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