SkyTrak 6042 Service Manual - Manual (Page 367)

8.135 Model 6042 Legacy Origin 7/02
Hydraulic System
11. Remove the locking inserts (Fig. 8 -91, 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 (Fig. 8 -91, 10), back-up ring (11)
and o-ring (12) from the head gland (7).
13. Remove the precision wearband (Fig. 8-91, 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 (Fig. 8-91, 4).
2. Discard all seals, back-up rings and o-rings. Replace
with new items from complete seal kits (Fig. 8-91, 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 (Fig. 8-91, 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
(Fig. 8-91, 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 (Fig. 8-91, 8) and head gland (7)
from the rod (6).
6. Remove the small o-ring (Fig. 8-91, 17) from inside
the piston (8).
7. Remove the precision wearbands (Fig. 8-91, 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
(Fig. 8-91, 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 (Fig. 8-91, 6) is straight. If it is
bent, install a new rod.
e. Side Tilt Carriage Cylinder Assembly
Note: Follow the general assembly instructions in
Section 8.13.3, “General Cylinder Assembly Instructions.”
1. If necessary, press the self-aligning bearings
(Fig. 8-91, 3) into the cylinder tube and rod ends.
The bearings should protrude equally from each side
of the eyelet.
2. Install the precision wearbands (Fig. 8-91, 18) into
the rear of the head gland, and the deep Z-seal (19),
rod wiper (20) and square ring (21) into the front of
the head gland (7). Orient the Z-seal edge (23). The
rod wiper lip (22) 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.
3. Install new oiled o-ring (Fig. 8-91, 12), back-up ring
(11) and oiled o-ring (10) on the head gland (7).
4. Fasten the rod end in a soft-jawed vise and put a
padded support below and near the threaded end of
the rod to help prevent damage to the rod.
5. Carefully slide the head gland (Fig. 8-91, 7) onto the
rod (6). If necessary, use a soft hammer to drive the
head gland onto the rod.
6. Install a new small oiled o-ring (Fig. 8-91, 17) inside
the rod end of the piston (8).