Hydraulics..Ongoing War Story

["Al Powell" <APOWELL@agcom.tamu.edu>]

Bob Kunz sent:

> Your description on a leaking servo and held pressure overnight can't
> be consistent with each other. Eventually, the fluid would all be returned
> to the reservoir, maybe you need to wait longer. Can you do that?
> 
> The leaking servo surely is not right. The dealer who installed it
> should replace it. The Bentley "just a few drops" really means that
> the drops are to empty the line when you disconnect it. The drops should
> not continue over time.
> 
> A possibility is that the servo is also using too much fluid per stroke.
> Since it's already leaking, it may leak more when in use. This could
> account for only 5 strokes. I believe there is a spec for fluid per
> stroke and you can measure this with the return line off.
> 
> If you get the right amount of fluid per stroke, then the accumulator
> has to be bad.
>
> Keep us informed..

OK, Bob.  Based on reading the manual, I mis-interpreted the test.  
When the return hose from reservoir to servo is dicsonnected, it will 
drain by gravity.  This is what I saw - but I was looking in the 
wrong place.  One must observe the fitting at the SERVO body and see 
if "more than a few drops" of fluid comes out of it.  When the system 
has correct pressure, "only a few drops" should escape from the servo 
body.

So I was looking at the wrong side of the connection, and observed 
the hose draining by gravity.  Duuuuhhhhhh.  Seems like I should hae 
realized this, as I kept thinking, "Shux, what would keep this from 
draining ANYtime??"  Interesting - I can simultaneously be perceptive 
and dumb.

The verdict to date is that the used PA I bought is faulty.  The h**l 
with used PAs.  I will take the excellent advice of many on this list 
and replace it with a new one.  Since this part seems to be 
perishable in the same sense as a water pump, I guess I'll do it 
right instead of monkeying with a used one.  I can buy a new one for 
under $250 anyway.
********** A Washington State Cougar in Aggieland (aTm) **********

Al Powell                           Voice:  409/845-2807
Ag Communications                   Fax:    409/862-1202
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"There are two kinds of truth.  There are real truths and made-up 
                    truths."   (Marion Berry)
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