-Recommended Hydraulic Fluid Specifications-

Oil should have anti-wear characteristics, excellent rust protection and contain additives to protect against foaming.

NOTE: Manufacturer uses hydraulic oil supplied by U.S. Oil Corporation with the following characteristics.
Viscosity Index 101
Grade 32
@ 100 F. it has a viscosity of 156
@210 F. it has a viscosity of 43.7

Cross-referencing to other manufacturers the following oils could be substituted.
Gulf Harmony 32A
Mobile D.T.E. 24
Shell Tellus 32
Texaco Rando H.D. 32



  1. Proper Viscosity: Choose a viscosity high enough to provide good sealing and proper lubrication, but not too high to cause significant pressure drops, loss of efficiencies or high power consumptions.

  2. Good Lubricity: Choose oil that has good lubricity, which is the ability to carry heavy loads while maintain low frictional properties.

  3. High Viscosity Index: The measure of the degree of change in the viscosity of fluid as change in temperature occurs. High index is the less the oil will thin when the temperature increases and low index the less the oil will thicken when temperature decreases.

  4. Stable & Non-degrading: Fluid should be thermal and shear stable and should resist breakdown from oxidation and bacteria.

  5. Low Compressibility: Compressibility is important when oil is subjected to higher pressure. High compressibility results in lower efficiency and higher apparent viscosity characteristics.

  6. Low Foaming: Low foaming is critical to performance. Excessive foaming can cause cavitation of the pump and premature wear

  7. High Heat Transfer: An important aid to remove heat generated in normal pumping and use of hydraulic fluids.

  8. Good Demulsibility: Demulsibility is the ability to resist emulsification and allow for separation and removal of water.

  9. Non-corrosive & Rust Inhibiters: Oils that are compatible with hydraulic components. Should contain effective rust inhibitors.

  10. Low Vapor Pressure: Assists in preventing cavitation and high wear rates of the hydraulic pump.

  11. Cleanliness:  Extremely important to use clean and non-contaminated hydraulic oil. With extremely tight tolerances built into pumps any contamination could destroy a pump. Even new oil should be filtered before using. A 10-Micron Medium is recommended.




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