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Revision B December 2013
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6.
Assorted Hoses, Pressure Fittings
These can be used to connect and/or isolate certain parts of a hydraulic circuit for
diagnosing hydraulic problems.
If you suspect problems do not operate the system. Diagnose and repair, or contact
Energy Absorption Systems Customer Service Department for assistance.
7.
High-Pressure Shut-Off Valve
The shut off valve can be used to choke off oil flow so that a "false" load can be put on
the pump and other components. With the valve assembled, it can be slowly shut off
while the equipment listed above records the data for making a proper diagnosis.
Hydraulic Fluid
1.
The Purpose of Oil
The main purpose of hydraulic fluid is to transfer power from the pump to the actuators but it
must also perform many other tasks which are critical to a
properly designed
system. First, the
oil must have good lubricity or be “slippery” so that the friction will be as low as possible to keep
metal-to-metal wearing at a minimum. Second, the viscosity or “thickness” must be in the proper
range at the operating temperature so that unwanted leakage will be at a minimum but will still
allow the oil to lubricate the close-fitting parts in the system. (Oil that is too thin will leak past
seals, valve spools, and the pump gears; oil that is too thick will not flow properly and cause the
pump to cavitate or starve.) Third, the oil must be compatible with the seals used in the system.
Fourth, there should also be additives in the oil to slow down the effects of rust, oxidation
(oxygen in the air combining with the oil 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.
2.
Selecting Fluids for Applications Outside
Dexron
®
III ATF’s Temperature
Range
When looking for fluids that can be used in place of Dexron
®
III ATF or for applications where
the operating temperature is outside the range of Dexron
®
III ATF the following specifications
should be discussed with your local oil distributor:
A. Fluid must be compatible with Buna-N sealing compounds.
B. The Pour Point must be below the lowest anticipated temperature that will be encountered.
C. Fluid shall also
contain rust or oxidation inhibitors as well as other detergent type inhibitors.
D. The viscosity (SUS) shall lie between 80 and 375
in the operating range, with the ideal
viscosity near 200 SUS.
E. The viscosity index shall be as high as possible. As an example, Dexron
®
III ATF has the
following
specs as listed by most oil manufacturers
:
[1] Viscosity (SUS)
37 deg. C [100 deg. F] 185 to 205
99 deg. C [210 deg. F] 45 to 55
[2] Pour Point -44 deg. C [-45 deg. F] to
-37 deg. C [-35 deg. F]
[3] Viscosity Index 145 to 165
Note:
In an emergency, for cold weather applications, SAE 10 W non-detergent oil mixed
by volume with no more than 30% #1 fuel oil or kerosene can be used.
