8.17
3507, 3508, 3509, 3512, 3513, 4007, 4008, 4009, 4012, 4013
Hydraulic System
8.9.2
General 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.
IMPORTANT:
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.
IMPORTANT:
DO NOT tamper with or attempt to adjust
the counterbalance valve cartridge. If adjustment is
necessary, replace the counterbalance valve with a new
part.
4. Extend the rod (
5
) to allow access to the base of the
cylinder.
IMPORTANT:
Protect the finish on 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 (
6
) from the barrel (
1
). A considerable amount
of force will be necessary to remove the head gland.
Carefully slide the head gland down along the rod
toward the rod eye end, away from the cylinder
barrel.
IMPORTANT:
When sliding the rod and piston assembly
out of the tube, prevent the threaded end of the tube
from damaging the piston. Keep the rod centered within
the tube to help prevent binding.
6. Carefully pull the rod assembly along with the head
gland out of the cylinder barrel.
7. Fasten the rod end in a soft-jawed vise, and put a
padded support under and near the threaded end of
the rod to help prevent damage to the rod.
8. Remove the set screw (
3
) from the piston (
4
).
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 the area of the bonded parts. Wipe off any hydraulic
oil, then heat the part(s) uniformly to break the bond. A
temperature of 149-204° C (300-400° F) will destroy the
bond. Avoid overheating, or the parts may become
distorted or damaged. Apply sufficient torque for removal
while the 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 (
4
) from the rod (
5
) and
carefully slide the head gland (
6
) off the end of the
rod.
10. Remove all seals, back-up rings and o-rings (
2
) from
the 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.
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.
Escaping hydraulic fluid under pressure can
penetrate the skin, causing death or serious
injury.
MAH0160
1
4
3
2
6
5
2
1
