JLG X20JP - X600AJ Service Manual - Manual (Page 211)

SECTION 5 - HYDRAULICS
3121623 – JLG Lift – 5-33
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 FUNC-
TIONS DISCONNECTED, ETC.) WHILE PERFORMING THE PROCE-
DURE 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 components,
which may result in unexpected vehicle/machine move-
ment.
NOTE: If a pump or motor is being replaced due to internaldam-
age, the remaining units (pump or motors) need to be
inspected for damage and contamination, and the entire
hydraulic system will need to be flushed and the fluid
replaced. Failure to do so may cause considerable dam-
age 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 locations, 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 fit-
ting 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 possible case
drain port, this ensures that the housing contains as much
oil as possible and offers the greatest amount of lubrica-
tion to the internal components.
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 real-
istic.
NOTE: Make certain that the oil being used to fill the component
housing is as clean as possible, and store the fill container
in such a way as to prevent it from becoming contami-
nated.