SECTION 4 - BASIC HYDRAULIC INFORMATION & SCHEMATICS
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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 contamination, 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 ensure that the air is bled from this line.
This can be accomplished by loosening the hose at
the fitting closest to 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 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.
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 installa-
tion is not realistic.
Make certain that the oil being used to fill the com-
ponent housing is as clean as possible. Store the fill
container in such a way as to prevent it from becom-
ing contaminated.
Install a 60 bar (or 1000 psi) pressure gauge in the
charge pressure gauge port in order to monitor the
charge pressure during start-up.
It is recommended that the external control input sig-
nal, (electrical connections for EDC), be disconnected at
the pump control until after initial 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.
"Jog" or slowly rotate the engine until charge pressure
starts to rise. Start the engine and run at the lowest pos-
sible 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.
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 deter-
mine the cause for improper pressure.
INADEQUATE CHARGE PRESSURE WILL AFFECT THE OPERATOR'S ABIL-
ITY TO CONTROL THE MACHINE.
Shut down the engine and connect the external control
input signal. Also reconnect the machine function(s), if
disconnected earlier. Start the engine, checking to be
certain the pump remains in neutral. With the engine at
normal operating RPM, slowly check for 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 reservoir level and add filtered fluid if needed.
The machine is now ready for operation.
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