HYDRAULIC SYSTEM RT880E SERVICE MANUAL
2-6 Published 11-10-2014, Control # 524-00
12. Repeat Steps 10 and 11 for the remaining two outrigger
cylinders.
13. Disconnect the return line from the telescope cylinder
and fully extend the boom.
14. Connect the return line and retract the boom. Replenish
the reservoir hydraulic oil level as necessary.
15. Disconnect the return lines from both front steer
cylinders and turn the front wheels to the extreme right.
16. Connect the return lines and turn the front wheels to the
extreme left and then back to center. Replenish the
reservoir hydraulic oil level as necessary.
17. Repeat Steps 15 and 16 for the rear steering cylinders.
18. Raise the crane on outriggers.
19. Disconnect the line from port A of the axle lockout valve.
20. Using a jack under the rear wheel on one side of the
crane, jack up the wheel to maximum travel.
21. Connect the line to port A of the axle lockout valve and
disconnect the line from Port B.
22. Repeat Step 19 using the other rear wheel.
23. Connect the line to port B of the axle lockout valve.
Energize the axle lockout valve. Replenish the reservoir
hydraulic oil level as necessary.
24. Disconnect the return line from the main hoist motor and
fully hoist up the hoist.
25. Connect the return line to the main hoist motor and fully
hoist down the hoist, then hoist up again. Replenish the
reservoir hydraulic oil level as necessary.
26. Repeat Steps 24 and 25 for the auxiliary hoist as
necessary.
27. Disconnect one of the lines from the swing motor and
drive the motor in the direction it will go.
28. Connect the line to the swing motor, then drive the swing
motor in the opposite direction until the boom is centered
and forward. Replenish the reservoir hydraulic oil level
as necessary.
When hydraulic oils are changed, recheck the reservoir
hydraulic oil level after brief system operation and add
hydraulic oil as required. Working reservoir capacity
(capacity to full mark) is 236 U.S. gal (894 l). Ensure the
crane is level and in the travel mode of operation when the
hydraulic system is being filled. The system must be filled
with all cylinders retracted. Fill the reservoir to the full mark
on the reservoir sight gauge. After the reservoir is filled,
operate all circuits and recheck the reservoir sight gauge.
Add hydraulic oil as required.
Removing Air from the Hydraulic System
Air entering the hydraulic oil will normally be removed
automatically by passage of the hydraulic oil over the baffles
in the hydraulic reservoir. If a component has been replaced,
the reservoir level is too low, or a leak develops in the suction
lines to the pumps, air can enter the system. If air becomes
entrapped in the hydraulic oil, it may be detectable in pumps
and motor operated components such as the swing
mechanism and hoist(s), because it can cause these units to
become noisy during operation. If noisy operation occurs,
first check the level of the hydraulic reservoir and replenish
as necessary. Then inspect for leaks in the suction lines
leading to the pumps.
Minute leaks may be hard to locate. If a leak is not readily
detectable, use the following way to check for it:
Seal all normal openings in the hydraulic system and the
reservoir. Using a positive means to control the pressure
(like a regulator), pressurize the hydraulic system to 2 to
4 psi (13.8 to 27.6 kPa/0.14 to 0.28 bar) and inspect all
joints and fittings for evidence of leaks. A soap solution
applied to the fittings and joints may also prove helpful in
detecting minute leaks while the system is pressurized.
Remove the pressure, repair any leaks found, and
reopen any openings (such as a vent) closed for
inspection. Refill the reservoir after completing any
repairs or service. Operate all hydraulic circuits several
times in both directions.
This action should return any entrapped air to the
reservoir where it can be removed from the hydraulic oil
by the baffles.
To remove entrapped air from telescope cylinders, lower
the boom to below horizontal and fully telescope the
boom in and out several times.
If the air is not readily removed, lower the boom to below
horizontal, extend the telescope cylinders as far as
practicable, and allow the boom to remain in this position
overnight. This should allow entrapped air to find its way
to the holding valve so that telescoping the boom IN the
next morning should force the air back to the reservoir.
Ensure the boom is first telescoped IN (not OUT) in the
CAUTION
When hydraulic oils are changed or added, ensure that
hydraulic oils of different manufacturers are of the same
specifications. However, discoloration may occur.
DANGER
Locate the machine on a firm supporting surface and
position the boom over the front on outriggers when
extending the boom at low angles.
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