Lull 6K Service Manual - Manual (Page 272)

Boom and Transfer
6-22 Service Manual — Models 644B, 6K, 844C, 8K, 1044C, 10K
13. 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.
14. Check condition of threads on rod, nut, and capscrews. Do not attempt
to repair damaged threads.
15. Inspect counterbalance valve cartridge (Item 5), 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.
16. Lubricate counterbalance valve cartridge O-rings with clean hydraulic
oil.
17. Install cartridge in manifold block and torque to 30–35 ft-lbs.
18. Lubricate new O-ring with hydraulic oil and install inside piston (seals
rod to piston).
19. 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.
20. Slide head (Item 13), stroke limiter (Item 12), and piston (Item 11) onto
rod (Item 14). Lubricate threads on rod with hydraulic oil and install rod
nut (Item 6). Torque rod nut to 850 ft-lbs.
21. Lubricate new seal and wear rings with hydraulic oil and install on
piston.
22. Lubricate threads on eight (8) capscrews (Item 15) with hydraulic oil.
Coat inside of barrel (Item 7) with hydraulic oil. To avoid damaging
seals during assembly, carefully insert rod and head into barrel. Install
capscrews until snug. Do not torque capscrews (instructions follow).
23. Following sequence shown in Fig. 6-10, torque capscrews to an initial
value of 30 ft-lbs. Follow sequence again and torque capscrews to a
final value of 90 ft-lbs.
24. If so equipped, install cylinder manifold block (Item 2) on cylinder barrel
with three (3) each lockwashers (Item 3) and capscrews (Item 4).
Tighten capscrews to 156 in-lbs.
25. Install two (2) connectors (Item 1) on cylinder manifold. Torque
connectors to 85–95 ft-lbs.
26. If necessary, remove grease fitting covers (Items 9 and 17) and grease
fittings (Items 10 and 18) from cylinder. Inspect and replace if
damaged. Install and tighten fittings 1.5 to 3 turns past finger tight.
27. Lubricate grease fittings with EP lithium based grease.