PGP/PGM 300 Series
Service Manual HY09-SM300/US
11
Parker Hannifin Corporation
Gear Pump Division
Youngstown, OH
Lubrication and Oil
Recommendations
All parts, with the exception of the outboard bearing,
are lubricated by the hydraulic oil in the circuit.
Particular attention must be paid to keep clean oil in
the circuit system. Whenever there is a pump or
motor failure, and there is reason to feel that metal
particles may be in the system, the oil must be
drained, the entire system flushed clean and any
filter screens thoroughly cleaned or replaced. New oil
should be supplied for the entire system. Oil suitable
and recommended for use in circuits involving
Parker's pumps and motors should meet the following
specifications:
Viscosity:
• 50 SSU minimum @ operating temperature
7500 SSU maximum @ starting temperature
• 150 to 225 SSU @ 100° F. (37.8°C.) (generally)
44 to 48 SSU @ 210° F. (98.9° C.) (generally)
Viscosity Index: 90 minimum
Aniline Point: 175 minimum
Recommended Additives: Foam depressant,
rust and oxidation inhibitors. Filtration: 10 micron
recommended for maximum pump life.
Other Desirable Characteristics:
• Stability of physical and chemical characteristics.
• High demulsibility (low emulsibility) for separation
of water, air and contaminants.
• Resistant to the formation of gums, sludges, acids,
tars and varnishes.
• High lubricity and film strength.
General Recommendations:
A good-quality hydraulic oil conforming to the
characteristics listed above is essential to the
satisfactory performance and long life of any
hydraulic system.
The oil should be changed on regular schedules in
accordance with the manufacturer's recommendations,
and the system periodically flushed.
The oil temperature in the reservoir must not exceed
200° F., (93.3° C.) with a maximum temperature of
180° F. (82.2° C.) recommended. Higher temperatures
will result in rapid oil deterioration.
Reservoir capacity should equal in gallons the pump
output in gpm or the total gpm of all pumps, where
there is more than one in the system.
Oil poured into the reservoir should pass through a
100-mesh screen. Pour only clean oil from clean
containers into the reservoir. A 100-mesh screen may
be used in the suction line leading to the pump. A
suction filter should be of sufficient size to handle
twice the pump capacity. It must be cleaned and
checked regularly to avoid damage due to
contamination and cavitation.
Normal Temperatures:
O° F. (-1 8° C.) to 100° F. (37.8° C.) Ambient 100° F.
(37.8° C.) to 180° F. (82.2° C.) System. Be sure your
oil is recommended for the temperatures you expect to
encounter.
Cold Weather Operation:
Oils for use in cold weather should have a viscosity
not exceeding 7500 SSU at the minimum start-up
temperature. A pour point of at least 20° F. below
start-up temperature is recommended. Start-up
procedures should allow for a gradual warm-up until
the oil reaches a reasonably fluid state.
Continued on the following page.
Approximate SSU @
