More Hydraulics..Ongoing War Story

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

Well, I have achieved the most enviable position of all: a problem 
which involves one of two new parts, each from a different supplier, 
and each (natch) blames the other's part!!  (Don't ask me how I do 
this to myself - my wife just thinks of it as a "gift"...)

I have shared with you folks the deteriorating situation with my 
brake warning light - it flashes on when the brakes are used 
quickly; this comes after installing a used- guaranteed "bomb" from 
Shokan in my '90 200T.  Although it holds pressure overnight just 
fine, braking tests (about 5-7 pumps till no assist while drifting 
down a small hill) pointed to the bomb as faulty.  So far, so good..

BUT!  I called Shokan about it, and they asked if I had tested the 
brake servo.  They suggested that the symptoms I was experiencing 
(brake warning light comes on with any quick stab at the brakes, even 
a gentle one) is more characteristic of brake servo failure than 
"bomb" failure.  I had not tested for this...

The Bentley manual gives a simple test procedure for the brake servo, 
namely: with the system pressurized, disconnect the return line from 
the reservoir to the servo (connects to the top of the servo).  
Manual says that with pressure up (and yes, the "right" way to test 
this is with a gauge I don't have) ONLY a few drops of hydraulic 
fluid should escape from the line.  If more fluid comes out, it 
indicates a bad servo.  Simple enough.

Tried it.  Hydraulic fluid comes out in a slow but steady stream when 
the line is disconnected - whether pressure is up/engine off, or the 
engine is idling.  THIS seems to indicate a bad servo, which could be 
GOOD news, since we had a new Audi servo installed 5/95 and it's 
still under warranty!!

JEEEEZ.  So now I'm wondering if I have ONE or TWO bad parts.  Shokan 
says to go after the servo.  The dealer (90 miles away...) thinks 
it's the bomb.  Neither wants to replace things until I deal with 
the OTHER part.  I admit - it could even be both!!!  But how to tell, 
since this is all a linked system?

Here's my best idea, about which I invite comments.  The Bentley 
manual DOES show a series of tests which can be performed using VW 
pressure gauge #1441 - which screws into the pressure switch fitting 
and sundry other places.  After reading the manual, it appears that 
using this pressure gauge in two or three places can isolate the 
functions enough to determine WHICH part is faulty - or whether both 
are.  This may be the ONLY way to isolate the cause(s).  

Of course,. I don't have the gauge, nor does anyone in town.  
So I've made an appointment for Tuesday morning at the 90-mile-away 
dealer for them to do the gauge tests.  Shux, it's worth the money to 
find out what's wrong, and should take less than one hour.  I lose a 
day's annual leave to drive there and back, but this may come under 
the words of Big Claytie, our famous (former) gubernatorial 
candidate: "....lie back & enjoy it".

At this point, I am tempted to quote a gent from a Monty Python 
sketch who wanders into a doctor's office and shouts "My BRAIN 
hurts."  This car just knows it's one step ahead of me and won't let 
up.

Thank you for listening as this story becomes more complex.  Like I 
say, it's a "gift"...
********** A Washington State Cougar in Aggieland (aTm) **********

Al Powell                           Voice:  409/845-2807
Ag Communications                   Fax:    409/862-1202
107 Reed McDonald Bldg.             Email:  a-powell1@tamu.edu 
College Station, TX  77843-2112
W3 page - http://agcomwww.tamu.edu/agcom/rpe/alpage.htm

"There are two kinds of truth.  There are real truths and made-up 
                    truths."   (Marion Berry)
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