HYDRAULIC SYSTEM RT540E SERVICE MANUAL
2-6 Published 4-20-2015, Control # 502-01
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 395.99 l (104.6 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.
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
13.8 to 27.6 kPa (0.14 to 0.28 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.
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.
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.
In the event that air entrapment should persist, bleeding
of air by loosening various clamp and screw type fittings
may become necessary.
If the above procedures fail to eliminate air entrapment,
contact your authorized Grove Distributor.
Parts Replacement
Parts found damaged or out of tolerance when maintenance
is being performed should be replaced. Refer to the
Manitowoc Crane Care Parts Catalog for proper replacement
parts.
Directional Control Valves
The control valves that control the crane functions are
installed on the right side on the outside of the superstructure
side plate, and between the left and right superstructure side
plates under the main hoist.
Inspection
Inspect the control valves for visible damage, binding spools,
and evidence of leakage. If excessive internal leakage is
suspected during operation with a spool in its center position,
it is possible that the area between the spool and working
section bore of the valve body is worn beyond serviceable
DANGER
Tipping Hazard
To avoid death or serious injury, locate the machine on a
firm supporting surface and position the boom over the
front on outriggers when extending the boom at low
angles.
DANGER
Pressurized fluid can cause serious injury or death.
Extreme care must be used when removing any plugs or
restrictions from a hydraulic system suspected to have
entrapped air that may be pressurized.
DANGER
Pressurized fluid can cause serious injury or death. Do
not attempt to loosen fittings in pressurized lines or while
the hydraulic pumps are in operation.
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