Hydraulic Technical Info. > Oil

Hydraulic Info:     0il Recommendations

All parts, with the exception of a few items, are lubricated by the hydraulic oil in the circuit. Particular attention must be paid to keep the oil in the circuit clean. Whenever there is a hydraulic component failure (cylinder, pump, valve), and there is a 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 rec- ommended for use in circuiits involving pumps, motors and cylinders should meet the following specifications:

Other Desireable 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 Qn regular schedules in accordance with the manufacturers recommendations and the system peri- odically flushed.
• Oil operating temperature should not exceed 200° F. (93° C.) with a maximum of 180° F. (82° C.) generally
• recommended. 120° F to 140° F. (50° C. to 60° C.) is generally considered the optimum system operating temperatures. High temperatures result in rapid oil deterioration and may point out a need for an oil cooler or a larger reservoir. The nearer to optimum temperature, the longer the service life of the oil and the hydraulic components.
• The system 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.