Re: 87 5000CSQW - Hydraul fluid level varies a lot

["Peter Orban" <peter@amtsg6.ime.nrc.ca>]

> Subject: Re: 87 5000CSQW - Hydraul fluid level varies a lot
>
> >The problem is that the fluid level in the reservoir varies widely. After
> >my evening commute (DC / NO VA stop & go), the fluid is at the minimum
> >line or a little below. If I check a few hours later, the level is at 7/8
> >of max. My garage floor is pretty level so I know that's not it.

The hydraulic system has a pressure accumulator in it, the "bomb". It is a
sphere with a rubber membrane or blubber in it. On one side of the membrane
there is high pressure inert gas in it, on the other side the hydraulic fluid.
When the hydraulic system is at operational pressure the gas gets compressed
and its place is taken up by the fluid. When you shut down the engine the
hydraulic pressure slowly whithers away, the gas pushes back the fluid from the
bomb into the reservoir. Hence the varying fluid level. I think this is normal,
the only question is how long does it take for the pressure go down. The manual
should have some indication on this one.

Good luck, Peter

-- 
--
Peter E. Orban
National Research Council of Canada
e-mail: peter.orban@nrc.ca