SkyTrak 8042 Service Manual - Manual (Page 532)

8.117 Model 8042, 10042, 10054 Legacy Rev. 10/03
Hydraulic System
c. Attachment Tilt Cylinder Cleaning
1. Thoroughly clean the inner surface of the attachment
tilt cylinder with trichlorethylene or another approved
cleaner.
2. Discard all seals, back-up rings and o-rings. Replace
with new items from complete seal kits (18) 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.
d. Attachment Tilt Cylinder Inspection
1. Inspect internal surfaces and all parts for wear, damage,
etc. If the inner surface of the tube (3) 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. Inspect all other components for wear, damage, etc.
Clean parts with trichlorethylene.
4. Check that the rod (1) is straight. If it is bent, a new
rod must be installed.
e. Attachment Tilt Cylinder Assembly
Note: Follow Section 8.13.3, “General Cylinder
Assembly Instructions.”
1. Install the sealed outside diameter heavy-duty rod
wiper (13) into the outer end of the head gland (2). The
wiper lip (19) 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.
2. Install new oiled o-ring (10), back-up ring (9), oiled
o-ring (8), precision wearbands (11) and deep Z-seal
with rod back-up (12) onto the head gland (2)
orienting the edge (20).
3. Install the small new oiled o-ring (16) into the groove
in the end of the rod (1).
4. Install the precision wearband (14) and the capped
T-seal (15) onto the piston (7).
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.
5. Install the head gland (2) and piston (7) onto the rod
(1).
IMPORTANT: Protect the finish on the rod at all times.
Damage to the surface of the rod can cause seal failure.
6. 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. Apply
Loctite #271 (red) and install the locknut (5) onto the
rod (1). Torque the nut to 1735-1885 lb-ft (2352-2556
Nm).
7. Place new nylon balls (6) into the threaded holes of
the locknut (5). Insert the setscrews (4) into the
holes and tighten until the nylon balls are deformed
into the threads of the rod.
IMPORTANT: Avoid using excess force when clamping
the cylinder in a vise. Apply only enough force to hold the
cylinder securely.Excessive force can damage the cylinder.
8. Place the attachment tilt cylinder tube (3) in a soft-
jawed vise or other acceptable holding equipment if
possible.
IMPORTANT: When sliding the rod and piston assembly
in the tube, prevent the threaded end of the tube from
damaging the piston (7). Keep the rod centered within
the tube to help prevent binding.
9. Carefully insert the rod (1) with all attachments
straight into the tube (3).
10. Using a pin spanner wrench, thread the head gland
(2) completely into the tube (3). Torque to 300 ±50
lb-ft (407 ±68 Nm).
11. Apply Loctite #242 (blue) to the threads of the lock
screw (21) and thread into the flange of the head
gland (2). Torque to 3-4 lb-ft (4-5 Nm).
12. Using new oiled o-rings, thread the 4000 psi (276 bar)
counterbalance valve (22) and the pilot-operated
check valve (23) into the attachment tilt cylinder (24).
Torque to 30-35 lb-ft (41-47 Nm).
13. If necessary, install a grease fitting (25) into the
tapped hole in the end of the rod (1). Lubricate the
bushings (17) in the rod end through the grease
fitting with multi-purpose grease before the vehicle is
operated.