JLG X23J - X700AJ Service Manual - Manual (Page 460)

SECTION 5 - HYDRAULICS
5-34 – JLG Lift – 3121448
5.4 HYDRAULIC COMPONENT START-UP
PROCEDURES AND
RECOMMENDATIONS
From a hydrostatic component standpoint, the goal at
system start up is to put into functional operation, the
hydrostatic system in such a way as to preserve the
designed life span of the system. The following start-up
procedure should be adhered to whenever a new pump
or motor is initially installed into a machine, or a system
is restarted after either a pump or motor has been
removed and/or replaced.
THE FOLLOWING PROCEDURE MAY REQUIRE THE MACHINE TO
BE DISABLED (WHEELS RAISED OFF THE GROUND, WORK
FUNCTIONS DISCONNECTED, ETC.) WHILE PERFORMING THE
PROCEDURE IN ORDER TO PREVENT INJURY. TAKE NECESSARY
SAFETY PRECAUTIONS BEFORE MOVING THE VEHICLE/
MACHINE.
Prior to installing the pump and/or motor, inspect the
unit(s) for damage that may have been incurred during
shipping and handling. Make certain that all system com-
ponents (reservoir, hoses, valves, fittings, heat
exchanger, etc.) are clean prior to filling with fluid.
Fill the reservoir with recommended hydraulic fluid. This
fluid should be passed through a 10 micron (nominal, no
bypass) filter prior to entering the reservoir. The use of
contaminated fluid will cause damage to the compo-
nents, which may result in unexpected vehicle/machine
movement.
NOTE: If a pump or motor is being replaced due to internal-
damage, the remaining units (pump or motors)
need to be inspected for damage and contamina-
tion, and the entire hydraulic system will need to be
flushed and the fluid replaced. Failure to do so may
cause considerable damage to the entire system.
The inlet line leading from the reservoir to the pump must
be filled prior to start-up. Check the inlet line for property
tightened fittings and make sure it is free of restrictions
and air leaks.
NOTE: In most cases, the reservoir is above the pump inlet
so that the pressure head created by the higher oil
level helps to keep the inlet pressures within an
acceptable range and prevent high vacuum levels.
However, due to hose routing or low reservoir loca-
tions, there may be air trapped within this line. It is
important to assure that the air is bled from this
line.This can be accomplished by loosening the
hose at the fitting closest the pump. When oil
begins to flow, the line is full, the air has been
purged, and the fitting can be retightened to its
specified torque. If the tank needs to be pressurized
in order to start the flow of oil, a vacuum reading
should be taken at the inlet of the pump during
operation in order to verify that the pump is not
being asked to draw an inlet vacuum higher than it
is capable of.
Be certain to fill the pump and/or motor housing with
clean hydraulic fluid prior to start up. Fill the housing by
pouring filtered oil into the upper case drain port.
NOTE: It is highly recommended to use the highest possi-
ble case drain port, this ensures that the housing
contains as much oil as possible and offers the
greatest amount of lubrication to the internal com-
ponents.
NOTE: In initial start-up conditions, it may be convenient to
fill the housing, just prior to installing the case drain
line. Component, (especially motor), location may
be such that access to the case drain port after
installation is not realistic.
NOTE: Make certain that the oil being used to fill the com-
ponent housing is as clean as possible, and store
the fill container in such a way as to prevent it from
becoming contaminated.