Hydraulic System And Component Maintenance And Repair - Skyjack SJ-7027 Operating, Maintenance And Parts Manual

HYDRAULIC SYSTEM AND COMPONENT
MAINTENANCE AND REPAIR
The following points should be kept in mind when
working on the hydraulic system or any component:
1. Any structure has limits of strength and
durability. To prevent failure of structural parts
of hydraulic components, relief valves which
limit pressure to safe operating values are
included in the hydraulic circuits.
2. Tolerance of working parts in the hydraulic
system are very close. Even small amounts of
dirt or foreign material in the system can cause
wear or damage to components, as well as
general faulty operation of the hydraulic
system. Every precaution must be taken to
assure absolute cleanliness of the hydraulic oil.
3. Samples of hydraulic oil should be drawn from
the reservoir every six months. These samples
should be about two quarts and should be
taken while the oil is warmed through normal
operation of the system. If possible, the sample
should be analyzed by a qualified lubrication
specialist to determine whether it is suitable
for further use. The intervals between oil
changes depend on operating conditions and
on the care used in keeping the oil clean.
4. Whenever there is a hydraulic system failure
which gives reason to believe that there are
metal particles or foreign materials in the
system, drain and flush the entire system and
replace the filter cartridges. A complete
change of oil must be made under these
circumstances.
5. Whenever the hydraulic system is drained,
check the magnets in the hydraulic reservoir
for metal particles. If metal particles are
present, flush the entire system and add a new
change of oil. The presence of metal particles
also may indicate the possibility of imminent
component failure. A very small amount of fine
particles is normal.
6. DO NOT use synthetic or fire resistant oils in
this personnel lift. Use ATF Dexron III (ESSO)
or equivalent hydraulic oil. For conditions
causing oil temperatures below -31° F (-35° C)
and above 122° F (50° C) consult Skyjack Inc.
SJ-600 Series Engine Powered 112715
June 2001
7. All containers and funnels used in handling
hydraulic oil must be absolutely clean. Use a
funnel when necessary for filling the hydraulic
oil reservoir, and fill the reservoir only through
the filler opening. The use of cloth to strain the
oil should be avoided to prevent lint from
getting into the system.
8. When removing any hydraulic component, be
sure to cap and tag all hydraulic lines involved.
Also, plug the ports of the removed
components.
9. All hydraulic components
disassembled in spotlessly clean surroundings.
During disassembly, pay particular attention to
the identification of parts to assure proper
reassembly. Clean all metal parts in a clean
mineral oil solvent. Be sure to thoroughly clean
all internal passages. After the parts have been
dried thoroughly, lay them on a clean, lint-free
surface for inspection.
10. Replace all o-rings and seals when overhauling
any component. Lubricate all parts with clean
hydraulic oil before reassembly. Use small
amounts of petroleum jelly to hold o-rings in
place during assembly.
11. Be sure to replace any lost hydraulic oil when
completing the installation of the repaired
component, and bleed any air from the system
when required.
12. All hydraulic connections must be kept tight.
A loose connection in a pressure line will permit
the oil to leak out or air to be drawn into the
system. Air in the system can cause damage
to the components and noisy or erratic system
operation.
MAINTENANCE. Three
procedures have the greatest effect on hydraulic
system performance, efficiency and life. Yet, the very
simplicity of them may be reasons they are so often
overlooked. What are they? Simply these:
1. Change filters regularly.
2. Maintain a sufficient quantity of clean hydraulic
oil of the proper type and viscosity in the
hydraulic reservoir.
3. Keep all connections tight.
must be
simple maintenance
SECTION 5, Page 3