Hydraulic System And Component Maintenance And Repair - Skyjack SJ 8831E Maintenance And Parts Manual

Hydraulic System And Component
Maintenance And Repair
The following points should be kept in mind when work-
ing 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 hydrau-
lic circuits.
2. Tolerance of working parts in the hydraulic sys-
tem 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
work platform. 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-800 Series E Battery Powered
119153
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 compo-
nents.
9. All hydraulic components must be disassembled
in spotlessly clean surroundings. During disas-
sembly, pay particular attention to the identifica-
tion 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 inspec-
tion.
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 com-
ponent, 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 simple maintenance proce-
dures 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.
SECTION 5, Page 3