SkyTrak 6036 Service Manual - Manual (Page 184)

Hydraulic System
8-32 6036, 6042, 8042, 10042, 10054
4. Label, disconnect and cap or plug hydraulic hoses in
relation to the cylinder.
5. Attach a suitable sling to an appropriate lifting device
and to the cylinder. Make sure the device used can
actually support the cylinder.
6. Remove the lock bolt and/or any retaining clips
securing the cylinder pins. Remove the cylinder pins.
7. Remove the cylinder.
8. Wipe up any hydraulic fluid spillage in, on, near and
around the machine, work area and tools.
b. Cylinder Disassembly
1. Clean the cylinder with a suitable cleaner before
disassembly. Remove all dirt, debris and grease
from the cylinder.
2. Clamp the barrel end of the cylinder in a soft-jawed
vise or other acceptable holding equipment if
possible.
Note: Avoid using excessive force when clamping the
cylinder in a vise. Apply only enough force to hold the
cylinder securely. Excessive force can damage the
cylinder tube.
3. If applicable, remove the counterbalance valve from
the side of the cylinder barrel.
Note: DO NOT tamper with or attempt to adjust the
counterbalance valve cartridge. If adjustment or
replacement is necessary, replace the counterbalance
valve with a new part.
4. Extend the rod as required to allow access to the
base of the cylinder.
Note: Protect the finish of the rod at all times. Damage
to the surface of the rod can cause seal failure.
5. Using a pin spanner wrench, unscrew the head
gland from the tube. A considerable amount of force
will be needed to remove the head gland. Carefully
slide the head gland down along the rod toward the
rod eye, away from the cylinder barrel.
Note: When sliding the rod and piston assembly out of
the barrel, prevent the threaded end of the barrel from
damaging the piston. Keep the rod centered within the
barrel to help prevent binding.
6. Carefully pull the rod assembly along with the head
gland out of the cylinder barrel.
7. Fasten the rod eye in a soft-jawed vise, and place a
padded support under and near the threaded end of
the rod to prevent any damage to the rod.
8. Remove the set screw from the piston head.
Note: It may be necessary to apply heat to break the
bond of the sealant between the piston and the rod
before the piston can be removed.
Some cylinder parts are sealed with a special organic
sealant and locking compound. Before attempting to
disassemble these parts, remove any accessible seals
from area of bonded parts. Wipe off any hydraulic oil, then
heat part(s) uniformly to break bond. A temperature of
300-400° F (149-204° C) will destroy bond. Avoid
overheating, or parts may become distorted or damaged.
Apply sufficient torque for removal while parts are still hot.
The sealant often leaves a white, powdery residue on
threads and other parts, which must be removed by
brushing with a soft brass wire brush prior to reassembly.
9. Remove the piston head from the rod and carefully
slide the head gland off the end of the rod.
10. Remove all seals, back-up rings and o-rings from
piston head and all seals, back-up rings and o-rings
from the head gland.
Note: The head gland bearing will need to be inspected
to determine if replacement is necessary.
DO NOT attempt to salvage cylinder seals, sealing rings
or o-rings. ALWAYS use a new, complete seal kit when
rebuilding hydraulic components. Consult the parts
catalog for ordering information.
c. Cylinder Cleaning Instructions
1. Discard all seals, back-up rings and o-rings. Replace
with new items from seal kit to ensure proper
cylinder function.
2. 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 or parts, it can be removed by using a soft
WARNING
Significant pressure may be trapped inside the
cylinder. Exercise caution when removing a
counterbalance valve or a pilot-operated check valve
from a cylinder.
MH6520