HYDRAULIC SYSTEM
SUB-SECTION 4A
GENERAL MAINTENANCE
7. Disconnect the hoses attached to the retract side of the
telescope cylinders at the hose reel or at the base of the
The following points should be kept in mind when working
boom. Extend the boom to force the flushing oil from the
on the hydraulic system or any hydraulic component:
telescope cylinders.
8. Reconnect the telescope cylinder hoses and retract the
1. Any structure has limits of strength and durability. To
boom. Add clean oil to the reservoir as required to maintain
prevent the failure of structural parts of hydraulic com-
the proper oil level.
ponents, relief valves which limit pressure to safe operating
values are included in the hydraulic circuits. The settings of
9. Disconnect the hoses attached to the retract side of the
these relief valves must never be changed, except as de-
outrigger extension cylinders, and then extend the out-
scribed under the topic Relief Valve Adjustment.
riggers fully. This will force the flushing oil from the cylin-
ders.
2. Tolerances of working parts in the hydraulic system are
very close. Even small amounts of dirt or foreign material in
10. Reconnect the hoses to the outrigger extension cylin-
the system can cause wear or damage to components, as
ders, and retract the outriggers. Add oil to the reservoir as
well as generally faulty operation of the system. Every pre-
required to maintain the proper oil level.
caution must be taken to assure absolute cleanliness of the
hydraulic oil.
11. Disconnect the hoses attached to the retract side of the
outrigger lift cylinders, and then lift the machine off the
ground. This will force the flushing oil out of the cylinders.
3. Samples of hydraulic oil should be drawn from the reser-
voir every six months. These samples should be about two
12. Reconnect the hoses and lower the machine to the
quarts, and should be taken while the oil is warmed through
ground. Add oil to the reservoir as required to maintain the
normal operation. If possible, the sample should be ana-
proper oil level.
lyzed by a qualified lubrication specialist to determine
whether it is suitable for further use. The interval between
13. Operate the steering wheel left and right several times
oil changes, depend on operating conditions, and on the care
to force the flushing oil in the steering system back to the
used in keeping the oil clean.
reservoir.
4. Whenever there is a hydraulic component failure which
14. Swing the upper of the machine in both directions, and
gives reason to believe that than are metal particles or
operate the winches in both directions several times to
other foreign materials in the system, drain and flush the
force the flushing oil in these motors back to the reservoir.
entire system, and replace the filter cartridges. A complete
change of hydraulic oil must be made under these circum-
15. Replace the return line filters. Cycle the machine
stances.
through all crane functions and operate the steering and out-
rigger systems several times to filter out any remaining con-
5. Whenever the hydraulic system is drained, check the
tamination.
magnetics at the bottom of the reservoir for metal particles.
If metal particles are present, flush the system and add a
16. Another method of cleaning the hydraulic system is to
new charge of oil. The presence of metal particles also may
use a self-contained batch filter unit, such as the Schroeder
indicate the possibility of imminent component failure.
Brothers Filter Buggy, to filter the oil in the reservoir.
It is necessary with this method to cycle all the machine's
6. Do not use synthetic or fire resistant oils in this ma-
functions periodically to circulate unfiltered oil from the
chine. The packings in this system are designed for a good
actuators back to the reservoir for filtering.
grade mineral oil.
7. All containers and funnels used in handling hydraulic oil
NOTE
must be absolutely clean. Use a funnel with a 200 mesh
It is recommended that the hydraulic oil be filtered
screen for filling the hydraulic oil reservoir, and fill the
periodically using a self-contained batch filtering unit.
reservoir only through the filler opening. The use of cloth
if it is available, to keep the contamination level to a
to strain the oil should be avoided to prevent lint from
minimum.
getting into the system.
4A-2
