Removing Air From The Hydraulic System - Manitowoc Grove TMS700E Service And Maintenance Manual

TMS700E SERVICE MANUAL
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. Disconnect the return line from the main hoist motor and
fully hoist up the hoist.
18. 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.
19. Repeat Steps 17 and 18 for the auxiliary hoist as
necessary.
20. Disconnect one of the lines from the swing motor and
drive the motor in the direction it will go.
21. 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.
CAUTION
When hydraulic oils are changed or added, ensure that
hydraulic oils of different manufacturers are of the same
specifications, however, discoloration (milkiness) may
occur.
When hydraulic oils are changed, recheck the reservoir
hydraulic oil level after brief system operation and add
hydraulic oil as required. Working reservoir capacity (to full
mark) is 507 l (134 U.S. gal). 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.
Grove
Small 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
0.138 to 0.276 bar (2 to 4 psi) 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.
Locate the machine on a firm supporting surface and
position the boom over the front on outriggers when
extending the boom at low angles.
• 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
morning. Telescoping OUT may cause air to be forced
back into a cylinder.
Extreme care must be used when removing any plugs or
restrictions from a hydraulic system suspected to have
entrapped air that may be pressurized.
• Entrapped air may be removed from cylinders having
wet rods by cycling. On certain cylinders, a plugged port
is provided on the rod end to bleed off entrapped air.
Do not attempt to loosen fittings in pressurized lines or
while the hydraulic pumps are in operation.
Published 01-29-2015, Control # 512-01
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