Occasional brake warning

[Doug Rudoff <drudoff@spry.com>]

In the month and half I've had my '92 100CSQ the brake warning symbol has
gone on three times [the symbol is a circle with arcs on either side.
Somthing like "(0)"].

The was first time was about four weeks ago it went on was about a minute
after I showed a friend how the self-diagnostic button works. The second
time was the following day. I checked the brake fluid level, which was
fine. When I restarted the car the warning symbol wasn't there and it
displayed "OK". The third time was this morning as soon as I left the
local Audi dealer's service department aften an oil change.

Since nothing was found during the pre-purchase inspection (done at an
independent shop) and the inspection done with the oil change, I assume
there's no obvious problem. However, they weren't aware of the brake
warning. According to the pre-purchase inspection the brakes had about 70%
of their pads. 

Any ideas?

TIA

Doug Rudoff                 Seattle, WA                     drudoff@spry.com