to form sludge), foaming and water settling to the bottom of the reservoir. Fifth, the oil must be able to pour or flow at the lowest expected temperature so that the oil can reach or get into the pump. For all of the reasons just listed, automatic transmission fluid (ATF Dextron B) was found in most cases to be the best readily available fluid for the job in most climate conditions.
b. Selecting Fluids for Applications Outside of a TFS Temperature Range When looking for fluids that can be used in the place of automatic transmission fluid or for applications where the operating temperature is outside of the range of automatic transmission fluid, the following specifications should be discussed with your local oil distributor:
1.Fluid must be compatible with Buna N sealing compounds.
2.The Pour Point must be below the lowest anticipated temperature that will be encountered.
3.It should contain rust and Oxidation as well as other detergent type inhibitors.
4.The Viscosity (SUS) should lie between 80 as a minimum and 375 as a maximum in the operating range with the ideal viscosity near 200 SUS.
5.The viscosity index should be as high as possible.
As an example, automatic transmission fluid (ATF) has the following specifications as listed by most oil manufacturers.
A. Viscosity (SUS) 185 to 205 @ 100OF
Viscosity (SUS) 45 to 50 @ 210OF
B. Pour Point 450F to 350F.
C. Viscosity Index 145 to 165
Note: In an emergency for cold weather applications SAE 1OW non detergent oil mixed by volume with no more than 30% #1 fuel oil or kerosene can be used.
11.Hydraulic Pump Priming A. New Installations:
New system installations, as well as those that are disassembled for repair, require proper priming to avoid possible pump failure. A pump is said to be "primed" when the internal cavity is full of oil and the air has been expelled. If needed, prime a pump as follows:
1."Crack" or remove the high pressure line at or near the cylinder.
2."Jog" the handle until oil flow is clear. (Air is absent.)
3.Retighten or replace hose.
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