Lull 6K Service Manual - Manual (Page 266)

Boom and Transfer
6-16 Service Manual — Models 644B, 6K, 844C, 8K, 1044C, 10K
16. 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 or replacing the entire cartridge.
17. Lubricate counterbalance valve cartridge O-rings with clean hydraulic
oil.
18. Install cartridge in manifold block and torque to 30–35 ft-lbs.
19. Install O-ring plug (Item 6) in manifold block and torque to 70–80 ft-lbs.
20. Install O-ring plug (Item 7) in manifold block and torque to
125–145 in-lbs.
21. Lubricate new O-ring with hydraulic oil and install inside piston (seals
rod to piston).
22. 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.
23. Slide head (Item 12) and piston (Item 10) onto rod (Item 13). Lubricate
threads on rod with hydraulic oil and install rod nut (Item 9). Torque rod
nut to 850 ft-lbs.
24. Lubricate new seal and wear rings with hydraulic oil and install on
piston.
25. Lubricate threads on eight (8) capscrews (Item 11) with hydraulic oil.
Coat inside of barrel (Item 5) 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).
26. 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.
Fig. 6-10: Head Capscrew Torque Sequence
27. Install two (2) elbows (Item 1) on cylinder manifold. Torque elbow nuts
to 58–63 ft-lbs.
28. Lubricate grease fittings with EP lithium based grease.
1
2
3
4
5 6
7
8
K1
0
2
4