Lull 6K Service Manual - Manual (Page 395)

Boom and Transfer
Service Manual — Models 644B, 6K, 844C, 8K, 1044C, 10K 6-145
5. Remove eight (8) capscrews (Item 9) securing rod bearing head
(Item 8) to cylinder barrel.
6. Remove cylinder rod (Item 10) from cylinder barrel (Item 4).
CAUTION: To prevent possible damage to components, support rod and
head; do not wiggle rod or head back and forth during
removal.
7. Remove rod nut (Item 5), piston (Item 7), and rod bearing head from
cylinder rod.
8. Remove the two (2) elbows (Item 6) from the cylinder manifold block.
9. Remove four (4) O-ring plugs (Item 1) from cylinder manifold block.
10. Remove all O-rings, wear rings, and backup rings from cylinder
components and discard.
11. Thoroughly clean components with solvent and dry with compressed
air. Inspect and replace if damaged.
12. Inspect inner surface of barrel, outer surface of piston, and length of
rod for scratches and scoring. If barrel, piston, or rod is damaged, it
must be replaced.
13. Check condition of threads on rod, nut, and capscrews. Do not attempt
to repair damaged threads.
14. Inspect counterbalance valve cartridge (Item 8), including O-rings, for
condition and replace as necessary. Do not disassemble the cartridge.
Service to counterbalance valve cartridges is limited to installing new
O-rings and replacing the entire cartridge.
15. Lubricate counterbalance valve cartridge O-rings with clean hydraulic
oil.
16. Install valve cartridge (Item 2) in manifold block and torque to
40–45 ft-lbs.
17. Install valve cartridge (Item 3) in manifold block and torque to
150–160 ft-lbs.
18. Install four O-ring plugs (Item 1) in manifold block and torque to
125–145 in-lbs.
19. Lubricate new O-ring with hydraulic oil and install inside piston (seals
rod to piston).
20. Lubricate new O-ring, backup ring, seals, and wear rings with hydraulic
oil and install on head. Using a seal driver, install new wiper seal in
head. Lubricate wiper seal with hydraulic oil.
21. Slide rod bearing head (Item 8) and piston (Item 7) onto rod (Item 10).
Lubricate threads on rod with hydraulic oil and install rod nut (Item 5).
Torque rod nut to 550 ft-lbs.
22. Lubricate new seal and wear rings with hydraulic oil and install on
piston.