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.
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.
Oil should be changed in regular schedules in
accordance with the manufacturer's recommendations,
and the system should also be periodically flushed.
Oil temperature in 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 @
Service Manual HY09-SM030/031/050/051/US
Lubrication and Oil Recommendations
Series PGP 030/031 Series PGP 050/051
