More Brake Problems

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

OK, Audi Geniusii.....

Shre your thoughts with me on this one.

The car: 1990 200T.  63K miles.

As some of you will recall, we had no brake assist until the car had 
run for about 45 seconds in the AM.  Brake warning light 
stayed on through this period as well; turned off when 
pressure came up.  

Replaced PA with used one from Shokan.  Situation improved for about 
two weeks, then brake assist began to lag again after first start in 
am; brake light also began staying on.  Called Shokan and they won't 
refund - just issue a credit or sell me a rebuilt one for about $120 
more.  No thanks...

AudiOnly sold me a used, pressure tested, guaranteed PA.  Problem 
disappeared for about 48 hours, then the brake warning light started 
coming on, altho assist seemed to be OK.  I did my own test on the 
hydraulic system (as per the Bentley..) and thought it showed a bad 
brake servo.   The power brake serve had been replaced with a new 
Audi unit about four months before this began.  

At this point, I took the car 90 miles to the nearest dealer, who 
tested the system and said that 1)  the brake servo was OK (I read 
the test instuctions wrong) and 2)  the system was putting out 1800 
PSI, which indicates that the hydraulic pump is generating pressure 
OK. 

But the damn brake light NOW stays on 'most all the time!!!  Oh, it 
might go out for a few minutes, but it's at random times as far as I 
can discern...there's no pattern.

So - I *WAS* ready to be convinced the only problem was a faulty 
pressure warning light, because there was no other problem appearing.  
The switch screws into the brake servo and is easy to replace.

But TODAY, my wife said the brakes felt spongy twice when she started 
it after it had been sitting for 3+ hours.

I would SURE welcome opinions and suggestions on how to diagnose and 
solve this damn problem.  I am not willing to go to the dealer and 
let them start hanging $300 to $1000 hydraulic parts on the car 
until they find what's wrong (seems to be their only approach 
to most problems...) but this is a potential safety hazard, and I 
GOTTA find a solution.

I am frustrated.  The Audi gods are givin' me the old horse laugh.  
Only good thing is that the Mariners may win their game tonight!

The floor is open to observations.  Maybe I'm just not thinking this 
thing through.....?


********** 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

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