Lull 6K Service Manual - Manual (Page 271)

Boom and Transfer
Service Manual — Models 644B, 6K, 844C, 8K, 1044C, 10K 6-21
a. Place socket wrench over counterbalance valve cartridge (Item 5).
Wrap a clean shop rag around the socket to cover the area of the
counterbalance valve cartridge.
b. Carefully and slowly, turn cartridge out of manifold block (Item 2) to
release pressure in cylinder.
3. Remove the counterbalance valve cartridge.
Note: Some Models — 644B-37 (S/N 354–), 644B-42 (S/N 116–), 6K-37
(S/N 205–), 6K-42 (S/N 102–), 844C-42 (S/N 264–), 8K-42 (S/N 161–),
1044C-42 (S/N 105–), 1044C-54 (S/N 107–), 10K-42 (S/N 107–), and
10K-54 (S/N 101–) — do not have a separate manifold blocks (Item 2)
attached to the cylinder barrel (Item 7). The counterbalance valve cartridge
(Item 5) will need to be removed from the cylinder barrel manifold block.
4. Slowly extend and retract cylinder by hand to remove most of the
hydraulic oil.
5. Remove eight (8) capscrews (Item 15) securing rod bearing head
(Item 13) to barrel.
6. Remove cylinder rod (Item 14) from cylinder barrel (Item 7).
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 6), piston (Item 11), stroke limiter (Item 12), and
rod bearing head from cylinder rod.
8. Remove the two (2) connectors (Item 1) from the cylinder manifold
block (Item 2).
9. If so equipped, remove three (3) each capscrews (Item 4) and
lockwashers (Item 3) securing cylinder manifold block to cylinder barrel
(Item 7). Remove manifold block.
10. Inspect bushings for damage. The following steps are necessary if
bushing(s) need to be replaced:
a. Remove bushing (Item 8) from cylinder barrel and/or remove
bushing (Item 16) from cylinder rod using a bushing driver and
hammer or press. Drive one bushing all the way through to remove
other bushing.
b. Install new bushings so they are flush with outer edge boss to 0.02"
below.
c. To ensure proper lubrication, make sure an adequate amount of
grease is applied to the grease fitting(s) after cylinder is reinstalled
on machine.
11. Remove all O-rings, wear rings, and backup rings from cylinder
components and discard.
12. Thoroughly clean components with solvent and dry with compressed
air.