Lull 944E-42 Service Manual - Manual (Page 505)

8.253 Model 644E-42/944E-42 Rev. 6/04
Hydraulic System
11. Remove the locking inserts (9) from their holes in the
head gland threads. Pry or drill out the insert as
required. DO NOT damage the head gland threads.
New locking inserts will be required for reassembly.
12. Remove the o-ring (10), back-up ring (11) and o-
ring (12) from the head gland (7).
13. Remove the precision wearband (13) and capped
T-seal (14) from the piston (8).
Note: The T-seal actually consists of four components; a
wide, flexible inner band, the flexible T-seal band itself,
and two supportive split caps that mount on either side of
the “T” itself.
c. Side Tilt Carriage Cylinder Cleaning
1. Remove all hydraulic fluid, dirt and debris from the
inner surface of the cylinder tube (4).
2. Discard all seals, back-up rings and o-rings. Replace
with new items from complete seal kits (15) to help
ensure proper cylinder function.
3. Clean all metal parts with an approved cleaning
solvent such as trichlorethylene. Carefully clean
cavities, grooves, threads, etc.
Note: If a white, powdery residue is present on threads
and parts, it can be removed. Clean the residue away
with a soft brass wire brush prior to reassembly, and
wipe with Loctite T cleaner before reinstallation.
4. Remove the locknut (16) from the rod (6).
Note: Loctite Threadlocker #271 (red) and 550-650 lb-ft
(746-881 Nm) of torque were applied to the locknut when
it was installed. It may be necessary to apply heat to
break the bond of the sealant between the locknut (16)
and the rod (6) before the parts can be removed. Some
parts of cylinders are sealed with a special organic
sealant and locking compound.
Before attempting to disassemble these parts, remove
any accessible seals from the area of the bonded joint.
Wipe off any hydraulic oil and heat the joint uniformly to
break the bond. A temperature of 300-400° F
(149-204° C) will destroy the bond. Avoid overheating or
the parts may become distorted or damaged. Apply
sufficient torque or pressure for removal while the parts
are still hot.
Breakdown of sealant will leave a white, powdery residue
on threads and parts. Clean the residue away with a soft
brass wire brush prior to reassembly, and wipe with
Loctite “T” cleaner before reinstallation.
5. Remove the piston (8) and head gland (7) from the
rod (6).
6. Remove the small o-ring (17) from inside the
piston (8).
7. Remove the precision wearbands (18), deep
Z-seal (19), rod wiper (20) and square ring (21) from
the head gland (7).
d. Side Tilt Carriage Cylinder Inspection
1. Inspect internal surfaces and all parts for wear,
damage, etc. If the inner surface of the tube (4) does
not display a smooth finish, or is scored or damaged
in any way, replace the tube. Often, dirty hydraulic
fluid causes failure of internal seals and damage to
the smooth surface within the tube.
2. Remove slight scratches on the piston, rod, or inner
surface of the tube with very fine grit emery cloth.
Use the emery cloth in a rotary motion to polish out
and blend the scratch(es) into the surrounding
surface.
3. Clean parts with trichlorethylene.
4. Check that the rod (6) is straight. If it is bent, install a
new rod.