Lull 6K Service Manual - Manual (Page 339)

Boom and Transfer
Service Manual — Models 644B, 6K, 844C, 8K, 1044C, 10K 6-89
15. Inspect counterbalance valve cartridges (Items 14 and 16), including
O-rings, for condition and replace as necessary. Do not disassemble
cartridges. Service to counterbalance valve cartridges is limited to
installing new O-rings and replacing the entire cartridge.
16. Lubricate a new O-ring with hydraulic oil and install it inside the piston
(seals the rod to the piston).
17. Lubricate new O-ring, backup ring, seals, and wear rings with hydraulic
oil and install them on the head. Using a seal driver, install a new wiper
seal in the head. Lubricate the wiper seal with hydraulic oil.
18. Slide the rod bearing head (Item 26), stroke limiter(s), (Item 25) and
piston (Item 24) onto the rod (Item 27). Lubricate threads on the rod
with hydraulic oil and install the rod nut (Item 21). Torque the rod nut to
300 ft-lbs for 2" diameter rods or 550 ft-lbs for 2.25" diameter rods.
19. Lubricate a new seal and wear rings with hydraulic oil and install them
on the piston.
20. Install the cylinder rod assembly in the cylinder barrel.
21. Using the three (3) holes in side the rod bearing head install a spanner
wrench and tighten the rod bearing head until it is snug against the
cylinder barrel. Make sure the threaded half hole in the head lines up
with the other half in the cylinder barrel.
22. Apply thread locking compound and install the setscrew (Item 18)
between the cylinder barrel and rod bearing head. Tighten until snug.
23. Lubricate the counterbalance valve cartridge O-rings with clean
hydraulic oil.
24. Install the valve cartridge (Item 14) in the manifold block and torque to
30–35 ft-lbs.
25. Install the valve cartridge (Item 16) in the manifold block and torque to
40–45 ft-lbs.
26. Install two (2) O-ring plugs (Item 13) in the manifold block and torque to
30–40 in-lbs.
27. Install two (2) connectors (Item 15) on the cylinder manifold block.
Torque the connectors to 85–95 ft-lbs.