Lull 944E-42 Service Manual - Manual (Page 490)

Hydraulic System
8.238 Model 644E-42/944E-42 Rev. 6/04
10. Secure the rod eyelet in a soft-jawed vise or other
suitable holding device. Place a padded support
below the threaded end of the rod to help prevent
damaging the rod.
11. Apply Loctite Primer “T” and Threadlocker #271
(red) to a new locknut (12) in accordance with Loctite
instructions. Install the nut onto the threaded end of
the rod. 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 (2).
12. Fasten the tube (2) in a soft-jawed vise or other
suitable holding device.
13. Lubricate the o-rings and the inside of the tube,
piston and head gland with clean, filtered hydraulic
oil. This will aid in installation.
IMPORTANT: Use a suitable installation tool or
compression sleeve to help prevent twisting or damaging
the seals and o-rings when installing the piston (10) and
head gland (8) 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 (11) straight and carefully insert the rod
into the tube (2). Avoid scratching, nicking or
damaging the tube while installing the rod.
15. Begin threading the head gland (8) into the tube (2).
Place the locking insert (9) in its hole in the head
gland threads just before the hole is threaded into
the tube. Use a suitable pin spanner wrench to
thread the head gland (8) completely into the
tube (2). Torque the head gland to 300-400 lb-ft
(407-542 Nm).
16. Using all new seals, thread the two pilot-operated
check valves (3), the pressure reducing valve (4) and
the five solenoid valves (5 and 6) into the manifold
block. Torque the four solenoid cartridges (6) to
35
- 40 lb - ft (47-54 Nm). Torque the check valves, the
pressure reducing valve, and the fifth solenoid
cartridge (5) to 35-40 lb-ft (47-54 Nm). Place the
solenoid coils on the cartridges and torque the
solenoid nuts to 4-6 lb-ft (48-72 lb-in) (5-8 Nm).
Refer to the Parts Manual for seal kits.
17. Press the two polylube bearings (22) into the base
end of the cylinder.
18. 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.
19. 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.
20. Retract the piston fully.
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