PGP/PGM 300 Series
Service Manual HY09-SM300/US
12
Parker Hannifin Corporation
Gear Pump Division
Youngstown, OH
The Use of Other Fluids:
• Automatic Transmission Fluid (ATF): In general, ATF
performance is satisfactory; however these fluids are
sometimes too expensive for normal use in hydraulic
systems.
• Diesel Fuel or Kerosene (Coal Oil): Though
sometimes used as dilutants for cold weather
operations, they are not recommended, as they
are not sufficiently refined.
• Fire Resistant Fluids: DO NOT USE ANY FIRE
RESISTANT FLUIDS OR NON-PETROLEUM OILS
WITHOUT CONSULTING OUR TECHNICAL SERVICE
DEPARTMENT.
• These suggestions are intended as a guide only.
OBTAIN YOUR FINAL FLUID RECOMMENDATIONS
FROM YOUR FLUID SUPPLIER.
Recommended Start-up
Procedure For New or
Rebuilt Pump
Before installing a new or rebuilt pump, back off
the main relief valve until the spring tension on the
adjusting screw is relieved. This will avoid the
possibility of immediate damage to the replacement
unit in the event that the relief valve setting had
been increased beyond the recommended operating
pressure, prior to removing the old unit.
Before connecting any lines to the pump, fill all ports
with clean oil to provide initial lubrication. This is
particularly important if the unit is located above the
oil reservoir.
After connecting the lines and mounting the
replacement unit, operate the pump at least two
minutes at no load and at low rpm (400 min.) During
this break-in period, the unit should run free and not
develop an excessive amount of heat. If the unit
operates properly, speed and pressure can then be
increased to normal operating settings.
Reset the main relief valve to its proper setting while
the pump is running at maximum operating engine
(motor) speed for the vehicle.
ALWAYS USE AN ACCURATE GAUGE
WHEN ADJUSTING THE RELIEF VALVE
PRESSURE SETTING.
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