Section 7 — Maintenance • 41
Notice
Change the oil if the sample has any of the charac-
teristics listed in Figure 7.1.
If making a visual inspection, compare the sample of oil
to a sample of new oil of the same type. Also, compare
it to previous samples taken from the same unit. Look for
the signs of oil deterioration listed in Figure 7.1.
There are uid contamination detector kits available
which allow for rapid, on-the-spot analysis of the hydraulic
system’s condition. Contact your Altec representative for
further information.
Oxidation produces varnishes that bake onto hot sur-
faces. Oxidation products are acidic and tend to attack
metal surfaces. This can damage pumps, motors, and
valves. High operating temperatures will increase the
rate of oxidation of the oil. The presence of water or air
in hydraulic oil also causes oxidation.
The presence of water may cause rust and corrosion. If
laboratory analysis or visual inspection indicate that the
oil is deteriorating prematurely, determine the cause of
the problem and correct it.
Changing Oil and Flushing the System
A properly maintained ltration system greatly extends
the useful life of the hydraulic oil. However, the oil will
eventually need to be replaced due to contaminants that
form during normal operation of the unit.
It is impossible to recommend an exact time interval for
oil changes due to varying conditions of unit use. Use
the following guidelines to determine when the hydraulic
oil should be changed.
• Change the oil as recommended by the checklists
in the Appendix.
• If a hydraulic component fails and contaminates the
system with metallic particles, change the component
and the oil immediately.
• In climates with a wide variation in operating tempera-
tures between summer and winter months, change
to the appropriate weight oil each spring and fall.
Replace the return line lter cartridge and ller breather
cap every time the hydraulic oil is changed. Also, clean
or replace the suction lter.
A signicant quantity of oil remains in the hydraulic system
when the reservoir is drained. Flush the system when the
oil is changed. This is especially important if the system
is heavily contaminated with metal particles.
If the oil is contaminated with water, it may not be neces-
sary to change the oil and ush the system. Follow the
instructions under Water Removal in this section.
The following equipment and supplies are necessary to
properly ush the hydraulic system.
• Approximately 13 gallons (49 l) of proper hydraulic
oil
• Three return line lter cartridges
• Clean, lint-free rags
• Breather (if component has not been replaced
within one year)
Caution
Spilled hydraulic oil creates slick surfaces and can
cause personnel to slip and/or fall. Keep the unit and
work areas clean.
Use the following procedure to ush the hydraulic sys-
tem.
1. If the oil is being changed because of contamination
due to hydraulic component failure, proceed to step
2. Otherwise, operate the unit to circulate the oil and
warm it to operating temperature. This will allow many
of the impurities to drain off in suspension.
2. Drain the oil reservoir completely.
Figure 7.1 — Hydraulic Oil Conditions
Condition Possible Cause
Dark color Oxidation; contamination
Cloudiness or milky appearance Presence of water or wax
Rancid or burned odor Oxidation
Increase in viscosity Oxidation; addition of improper uids; presence of water
Decrease in viscosity Addition of improper uids; additive deterioration
Separation of water or other uids from the oil Presence of water; addition of improper uids
Foreign particles or other visible contamination Contamination; emulsion of water with oil additives
To Next Page
Loading...