Disappearing (and reappearing) BRAKES - update

[amz at eskimo.com]

More info...  Got car back from shop.  Brakes worked fine again.  Until...
I sat in traffic (much like the other day) with the clutch pushed in.  It
seems as though the brakes only "drain" when the clutch is pushed all the
way in.  After a while (of having the clutch pedal in the "up" position),
the brakes return to normal.

Leaky clutch master or ????

* Please cc: my e-mail in addition to the QList *


-----Original Message-----

Had a strange thing happen to me yesterday.  Got car back from the shop
(clutch master replacement) on Friday.  Drove it for a few hours on
Saturday.  Brakes worked fine.  A little while later, the brake pedal seemed
to depress a bit lower than usual, but car stopped as usual.  Suddenly,
while driving in slow/stop-and-go traffic, the brake pedal went straight to
the floor.  Brakes DID apply at the very bottom.  However, car was only
going about 20 mph at the time.  Tried pumping and nothing changed.

Since I had 20 mph braking and thinking that I might have lost brake or
hydraulic fluid, I slowly drove to the Audi dealer that (luckily) was a mile
down the road.  By the time I got there, the brakes engaged with the pedal
halfway down.  A check under the hood showed full fluids.  I tried pumping
the pedal again and the top "half" just caused a slight hissing sound and
the lower half of the pedal gave full braking.

With the brakes improving (and not wanting to pay the dealer to diagnose the
problem), I took back roads to get home.  A couple of miles from the dealer,
the brakes returned totally to normal.  Car is back at the mechanic, but
(without popping the hood yet) they're initially stumped.

What the heck is/was going on???

** Please cc: my e-mail in addition to the QList **

Thanks in advance,

Andrejs

1988 5000sq