SkyTrak 6036 Service Manual - Manual (Page 327)

8.111 Model 6036 Legacy
Hydraulic System
5. Using a pin spanner wrench, unscrew the head
gland (Fig. 8-72, 7) from the tube (2). The head
gland was originally torqued to 300-400 lb/ft
(407-542 Nm), so a considerable amount of force is
required. Carefully slide the head gland down along
the rod toward the eyelet end, away from the cylinder
tube (2).
IMPORTANT: When sliding the rod and piston assembly
into the tube, prevent the threaded end of the tube from
damaging the piston (Fig. 8-72, 8). Keep the rod
centered within the tube to help prevent binding.
6. Carefully pull the rod (Fig. 8-72, 6) with all
attachments straight out of the tube (2).
7. Fasten the rear of the rod 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.
8. Remove the locking inserts (Fig. 8 -72, 9) from the
holes in the head gland threads. Pry or drill out the
inserts as required. DO NOT damage the head gland
threads. New locking inserts will be required for
reassembly.
9. Remove the setscrews (Fig. 8-72, 10 and 11) from
the piston (8). The setscrews are used to provide a
secondary lock on the piston. Pry or drill out the
setscrews as required. DO NOT damage the piston
threads. New setscrews will be required for
reassembly.
10. Remove the piston (Fig. 8-72, 8) from the rod
spacer (12) and rod (6). The piston was installed
with Loctite #241 and torqued to 300-400 lb/ft
(407-542 Nm).
Note: It may be necessary to apply heat to break the
bond of the sealant between piston (Fig. 8-72, 8) and
the rod (6) before the piston 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.
11. Remove the rod spacer (Fig. 8 -72, 12).
12. Remove both precision wearbands (Fig. 8-72, 13),
the piston seal (14) and the square ring (15) from the
piston (8).
13. From within the piston (Fig. 8 -72, 8), remove the
back-up rings (16), the o-ring (17) and the small
o-ring (18).
14. Remove the o-ring (Fig. 8-72, 19), back-up ring (20)
and o-ring (21) from the head gland (7). Remove
them from the rod (6).
15. Remove the head gland (Fig. 8 -72, 7) from the rod.
16. From within the head gland (Fig. 8 -72, 7), remove
the precision wearbands (22) and, if installed, the
buffer seal (29). Remove the square ring (23), the
sealed outside diameter heavy-duty rod wiper (24)
and the U-cup seal (25) from the other end.
c. Extend/Retract Cylinder Cleaning
1. Remove all hydraulic fluid, dirt and debris from the
inner surface of the cylinder tube (Fig. 8 -72, 2).
2. Discard all seals, back-up rings, o-rings, etc.
Replace with new items from complete seal kits
(Fig. 8 -72, 25 and 26) 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. Extend/Retract Cylinder Inspection
1. Inspect internal surfaces and all parts for wear, damage,
etc. If the inner surface of the tube (Fig. 8-72, 2) 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 -72, 6) is straight. If it is
bent, install a new rod.