Lull 944E-42 Service Manual User Manual
Page 489
8.237
Model 644E-42/944E-42
Rev. 6/04
Hydraulic System
IMPORTANT: When sliding the rod and piston assembly
in the tube, DO NOT damage the piston (10) by scraping
it against the threads in the tube. Keep the rod in line
with the tube to prevent binding.
6. Carefully withdraw the rod (11) straight out of the
tube (2). Keep the rod straight during withdrawal to
help avoid scratching, nicking or damaging the tube.
7. Secure the rod eyelet and remove the locknut (12)
from the threaded end of the rod. Discard the nut; a
new nut will be required for reassembly.
Note: Heating the nut to approximately 300° F (150° C)
may also be required to break the seal formed by the
Loctite Threadlocker #271 (red) applied to the nut when
installed. The application of significant force is required
to overcome the 1840-2025 lb-ft (2495-2745 Nm) of
torque the nut was tightened to when originally installed.
8. Remove the piston (10) from the rod (11).
9. Remove the small o-ring (13) from the piston.
Remove both precision wearbands (14) from the
piston (10). Remove the capped T-seal (15) from the
piston (10).
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” seal band.
10. Remove the head gland (8) from the rod (11).
11. Remove the o-ring (16), the back-up ring (17) and
the o-ring (18) from the head gland (8).
12. Remove the heavy-duty rod wiper (19). Remove the
precision wearband (20) and deep Z-seal with rod
back-up (21) from inside the head gland (8).
13. Inspect and remove the two polylube bearings (22)
from the base end of the cylinder.
c. Stabilizer Cylinder Internal Cleaning
1. Remove all hydraulic fluid, dirt and debris from the
inner surface of the cylinder.
2. Discard all seals, back-up rings and o-rings. Replace
with new items from a complete seal kit (23) 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.
d. Stabilizer Cylinder Inspection and Repair
1. Inspect all parts for wear and damage. If inner
surfaces of the cylinder (1) do not display an ultra-
smooth, polished finish, or are damaged in any way,
replace the damaged part. Often, dirty hydraulic fluid
causes failure of internal seals and damage to the
polished surfaces within the component.
2. Inspect the inside of the tube (2) for scoring and
other damage. If the tube is damaged, replace it with
a new tube.
3. Remove small scratches on the rod or inside of the
tube with very fine grit emery cloth. Use the emery
cloth in a rotary motion to polish out small
imperfections in the metal and blend scratch(es) into
the surrounding surface.
4. Clean the parts with trichlorethylene after repair.
5. Check that the rod (11) is straight. If the rod is bent,
install a new rod.
e. Stabilizer Cylinder Assembly
Note: Follow Section 8.14.3, “General Cylinder
Assembly Instructions.”
1. Install the deep Z-seal with rod back-up (21) into the
head gland (8), orienting the edge (24).
2. Install the precision wearband (20) into the head
gland (8).
3. Install the heavy-duty rod wiper (19) with the raised
portion of the lip seal (25) oriented toward the rod
eyelet. The wiper lip (25) should be toward the outer
end of the head gland and the seal lips toward the
inner end of the head gland. Use tools that will not
damage the seals.
4. Install new oiled o-ring (18), back-up ring (17) and
oiled o-ring (16) onto the head gland (8). If the
back-up ring is not flat on both sides, the side with
the arc must be toward the o-ring.
5. Install the head gland (8) onto the rod (11). If
necessary, use a soft hammer to drive the head
gland onto the rod.
6. Install the new small oiled o-ring (13) into the
piston (10).
7. Install the capped T-seal (15) onto the piston (10).
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” seal band.
8. Install the two precision wearbands (14) onto the
piston (10).