SECTION 5 - HYDRAULICS
5-40
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5.13 HYDRAULIC COMPONENT START-UP
PROCEDURES AND RECOMMENDATIONS
From a hydrostatic component standpoint, the goal at sys-
tem start up is to put into functional operation, the hydro-
static 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 DIS-
ABLED (WHEELS RAISED OFF THE GROUND, WORK FUNCTIONS DIS-
CONNECTED, 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.
1.
Fill the reservoir with recommended hydraulic
fluid. This fluid should be passed through a 10
micron (nominal, no bypass) filter prior to enter-
ing the reservoir. The use of contaminated fluid
will cause damage to the components, 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.
2.
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.
3.
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 con-
tains as much oil as possible and offers the greatest
amount of lubrication 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 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.
4.
Install a 60 bar (or 1000 psi) pressure gauge in
the charge pressure gauge port in order to mon-
itor the charge pressure during start-up.
5.
It is recommended that the external control
input signal, (electrical connections for EDC), be
disconnected at the pump control until after ini-
tial start-up. This will ensure that the pump
remains in its neutral position.
DO NOT START THE ENGINE UNLESS PUMP IS IN THE NEUTRAL POSI-
TION (0 DEGREES SWASHPLATE ANGLE). TAKE PRECAUTIONS TO PRE-
VENT MACHINE MOVEMENT IN CASE PUMP IS ACTUATED DURING
INITIAL START-UP.
6.
"Jog" or slowly rotate the 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 the engine on low idle, "crack", (loosen-don't
remove), the system lines at the motor(s). Continue
to run the engine at low idle and tighten the system
lines as soon as oil is observed to leak from them.
When oil is observed to "leak" at the motor the line is
full, the air has been purged, and the system hoses
should be retightened to their specified torque.
7.
Once charge pressure has been established,
increase speed to normal operating RPM. Charge
pressure should be as indicated in the pump
model code. If charge pressure is inadequate,
shut down and determine the cause for
improper pressure.
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