JLG 450A_AJ Series II Service Manual - Manual (Page 330)

SECTION 5 - HYDRAULICS
5-40 – JLG Lift – 3121180
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. Use the following start-
up procedure whenever a new pump or motor is installed
in a machine, or a system is restarted after a pump or
motor has been removed and reinstalled.
THE FOLLOWING PROCEDURE MAY REQUIRE MACHINE TO BE
DISABLED (WHEELS RAISED OFF THE GROUND, WORK FUNC-
TIONS DISCONNECTED, ETC.) WHILE PERFORMING THE PROCE-
DURE TO PREVENT INJURY. TAKE NECESSAR Y SAFETY
PRECAUTIONS BEFORE MOVING THE VEHICLE/MACHINE.
Before installing pump and/or motor, inspect unit(s) for
damage that may have been incurred during shipping and
handling. Make sure all system components (reservoir,
hoses, valves, fittings, heat exchanger, etc.) are clean
before filling with fluid.
Fill reservoir with recommended hydraulic fluid. This fluid
should be passed through a 10 micron (nominal, no
bypass) filter before entering reservoir. Using contami-
nated fluid can damage components, which may result in
unexpected vehicle/machine movement.
IF A PUMP OR MOTOR IS REPLACED DUE TO INTERNAL DAM-
AGE, REMAINING UNITS (PUMP OR MOTORS) NEED TO BE
INSPECTED FOR DAMAGE AND CONTAMINATION, AND THE
ENTIRE HYDRAULIC SYSTEM FLUSHED AND FLUID REPLACED.
FAILURE TO DO SO MAY CAUSE CONSIDERABLE DAMAGE TO
THE ENTIRE SYSTEM.
Inlet line from reservoir to pump must be filled prior to
start-up. Check inlet line for properly tightened fittings,
restrictions, and air leaks.
NOTE: In most cases, reservoir is above pump inlet so pres-
sure head created by higher oil level helps keep inlet
pressures within an acceptable range and prevent
high vacuum levels. However, due to hose routing or
low reservoir locations, air may be trapped within
this line and must be bled. Bleed air by loosening
hose at fitting closest to pump. When oil begins to
flow, line is full, air has been purged, and the fitting
can be retightened to specified torque. If tank needs
to be pressurized to start low of oil, take a vacuum
reading at pump inlet during operation to verify
pump is not being asked to draw an inlet vacuum
higher than its capability.
Fill pump and motor housing with clean hydraulic fluid
prior to start up. Fill housing by pouring filtered oil in
upper case drain port.
NOTE: It is highly recommended to use the highest possible
case drain port. This ensures housing contains as
much oil as possible and offers the greatest amount
of lubrication to internal components.
NOTE: In initial start-up conditions, it may be convenient to
fill the housing before installing the case drain line.
Component (especially motor) location may prevent
case drain port access after installation.
NOTE: Make certain oil used to fill the component housing
is as clean as possible and store the fill container
properly to prevent it from becoming contaminated.