Tri Tool 765RVC Hyrdaulic Power Supply - Manual (Page 17)

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Model 765 RVC Hydraulic Power Supply
92-0306 : Rev. 140715
In general, if a fluid that is not listed is to be used, select a high quality hydraulic fluid
that has the following properties:
· Viscosity at 40 ° C of between 30 and 46 centistokes (cSt)
· Viscosity index of at least 95.
· API gravity of between 30 and 33 ° .
The viscosity index is a measure of how much the fluid’s viscosity changes as its
temperature changes. The higher the viscosity index number the less the fluid’s
viscosity is effected by temperature and the better it is for use in the system. Most
ATF, Type F fluids have viscosity index numbers around 165 whereas, most standard
hydraulic fluids have viscosity index numbers around 100.
API gravity, is a measure of the density a hydraulic fluid compared to water. If the
API gravity is greater than 10, it is lighter and floats on water; if less than 10, it is
heavier and sinks. API gravity is used to compare the relative densities of hydraulic
fluids. For example, with two hydraulic fluids, the one with the higher API gravity will
float on the one with the lower API gravity. Although mathematically API gravity has
no units, it is referred to as being in “degrees”.