JLG 510AJ Service Manual - Manual (Page 272)

SECTION 5 - HYDRAULICS AND HYDRAULIC SCHEMATICS
5-52 – JLG Lift – 3121181
5.5 HYDRAULIC COMPONENT START-UP
PROCEDURES AND RECOMMENDATIONS
The goal at system start up is to put the hydrostatic system in
operation to preserve the designed system life span. Use the
following start-up procedure whenever a new pump or motor
is installed, or a system is restarted after a pump or motor has
been removed and/or replaced.
THE FOLLOWING PROCEDURE MAY REQUIRE MACHINE TO BE DISABLED
(WHEELS RAISED OFF THE GROUND, WORK FUNCTIONS DISCONNECTED, ETC.)
WHILE PERFORMING THE PROCEDURE TO PREVENT INJURY. TAKE NECESSARY
SAFETY PRECAUTIONS BEFORE MOVING THE VEHICLE/MACHINE.
Inspect pump and/or motor, unit(s) for damage that may have
occurred 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 prior to entering the reservoir. Use of contaminated fluid
will damage components and may result in unexpected vehi-
cle/machine movement.
NOTE: If a pump or motor is replaced due to internal damage,
inspect remaining units (pump or motors) for damage and
contamination. The entire hydraulic system will need to be
flushed and fluid replaced. Failure to do so may cause con-
siderable damage to entire system.
Inlet line leading from reservoir to pump must be filled before
start-up. Check inlet line for properly tightened fittings and
make sure it is free of restrictions and air leaks.
NOTE: In most cases, reservoir is above pump inlet so pressure
head created by higher oil level helps keep inlet pressures
within an acceptable range and prevent high vacuum lev-
els. However, due to hose routing or low reservoir locations,
there may be air trapped within this line. It is important to
bleed air is from this line. This can be accomplished by loos-
ening hose at fitting closest to pump. When oil begins to
flow, line is full, air has been purged, and fitting can be
retightened to specified torque. If tank needs to be pressur-
ized to start flow of oil, a vacuum reading should be taken
at inlet of pump during operation to verify pump is not
being asked to draw an inlet vacuum higher than it is
capable of.
Fill pump and/or motor housing with clean hydraulic fluid
before 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 greatest amount of lubrication to inter-
nal components.
NOTE: In initial start-up conditions, it may be convenient to fill
housing before installing 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 oil being used to fill component housing is as
clean as possible. Store fill container to prevent it from
becoming contaminated.
Install a 60 bar (or 1000 psi) pressure gauge in charge pressure
gauge port to monitor charge pressure during start-up.
It is recommended the external control input signal, (electrical
connections for EDC), be disconnected at pump control until
after initial start-up. This ensures pump remains in its neutral
position.
DO NOT START THE ENGINE UNLESS PUMP IS IN THE NEUTRAL POSITION (0
DEGREES SWASHPLATE ANGLE). TAKE PRECAUTIONS TO PREVENT MACHINE
MOVEMENT IN CASE PUMP IS ACTUATED DURING INITIAL START-UP.
"Jog" or slowly rotate engine until charge pressure starts to
rise. Start the engine and run at the lowest possible RPM until
charge pressure has been established. Excess air should be
bled from the system lines as close to the motors as possible.
NOTE: With engine on low idle, "crack", (loosen-don't remove), sys-
tem lines at motor(s). Continue to run engine at low idle
and tighten system lines as soon as oil is observed to leak
from them. When oil is observed to "leak" at motor the line
is full, air has been purged, and system hoses should be
retightened to specified torque.
Once charge pressure has been established, increase speed to
normal operating RPM. Charge pressure should be as indi-
cated in the pump model code. If charge pressure is inade-
quate, shut down and determine cause of improper pressure.
INADEQUATE CHARGE PRESSURE WILL AFFECT THE OPERATOR'S ABILITY TO
CONTROL THE MACHINE.
Shut down engine and connect external control input signal.
Reconnect machine function(s), if disconnected earlier. Start
engine, check pump remains in neutral. With engine at normal
operating RPM, slowly check forward and reverse machine
operation.
Charge pressure may slightly decrease during forward or
reverse operation. Continue to cycle slowly between forward
and reverse for at least five minutes.
Shut down engine, remove gauges, and plug ports. Check res-
ervoir level and add filtered fluid if needed.
Machine is now ready for operation.