SkyTrak 6036 Service Manual - Manual (Page 136)

Section 9. Hydraulic System
9-23 Model 6036 S/N 9B0499 and Before
9.2 CYLINDERS
Rebuild cylinders only in a clean, well lighted area
where you can carefully inspect all components. If
a cylinder is to remain dismantled for any lengthy
period, coat the metal parts that are to be reused
with a good preservative and place in protective
storage. Refer to specific instructions for removal,
rebuilding and installation of each cylinder.
a. General Disassembly Instructions
Warning !
Take care when applying heat to parts to
prevent severe burns. Avoid the use of exces-
sive heat which will damage parts and make
them unusable.
Some parts of cylinders are sealed with a “special
organic” sealant and locking compound. Before
you attempt 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
to 400 °F (149 to 204 °C) will destroy the bond
strength of the sealant. Avoid overheating or the
parts may become distorted or damaged. Apply
sufficient torque or pressure for removal while
parts are still hot. Breakdown of sealant will leave
a white powdery residue on threads and parts
which must be removed by brushing with a soft
brass wire brush prior to reassembly.
Do not attempt to salvage cylinder seals or sealing
rings. Any hydraulic component must always be
serviced with a complete seal kit during a compo-
nent rebuild. Repair kits are available.
b. General Cleaning Instructions
Clean all reusable metal parts thoroughly after
disassembly and prior to inspection. Use an
approved solvent such as trichlorethylene.
c. General Assembly Instructions
1. Before reassembly, be sure parts are clean
and free from foreign matter. Use an ap-
proved solvent such as trichlorethylene for
cleaning.
2. Protect the finish on the rod at all times.
Damage to the rod can cause premature seal
failure.
3. Use proper tool for specific installation task.
Clean tools required for installation before use.
Warning !
4. Do not overstretch seals, wipers and O-rings.
Make sure that seals, wipers and O-rings are
not twisted or distorted in their grooves.
5. Lubricate piston seals and seal installation
path with clean hydraulic oil from a filtered
supply.
6. Use a suitable compression tool when install-
ing glands into cylinders to prevent damage to
the seals and O-rings. Place a little hydraulic
oil on the seals and outside of glands to aid in
installation.
7. Follow the manufacturer’s instructions when
applying primer, locking or retaining com-
pounds which are specified in reassembly
procedures. The use of primer is recom-
mended in some cases to decrease cure time.
Allow sealant compounds to cure fully. The
curing process may be hastened by the use of
a heat gun to blow warm, dry air on the parts.
8. Following reassembly, test cylinder at low
operating pressure to be sure the piston and
rod are moving freely in both directions.
9. Increase the operating pressure to the maxi-
mum recommended for the cylinder and check
for external leakage and free movement in
both directions.
10. Prepare cylinder for installation by retracting
piston and capping and plugging the ports.
9.2.1 Boom Hoist Cylinder
a. Removal
1. Support the boom, Fig. 9.9, in a horizontal
position with blocking.
2. Engage the park lock, place the travel select
lever in neutral, and stop the engine.
3. Operate the hydraulic controls after the engine
has stopped to relieve any trapped pressure.
4. Support the cylinder with a sling or other
suitable device.
Relieve hydraulic pressure before servicing any
hydraulic component. Escaping hydraulic fluid
under pressure can penetrate the skin causing
serious injury.