Brake fluid sucked away

[Steinbru@VNET.IBM.COM]

It seems that brake fluid is being sucked into the vacuum
booster, does this indicate a bad booster or a bad master
cylinder?

I have replaced the MC, two wheel cylinders, the proportioning
valve, and NOW the leak is worse.  But I discovered where the
DOT3 is going --into the booster.  I had pumped a quart through
while looking for a leak under the car, near the wheels, anywhere
--nada.

Upon beginning the second quart, I detected fluid escaping where
the vacuum line goes into the booster.  Pulling it, I discovered
most of the first quart of fluid.  Apparently it was being sucked
into the engine bit by bit.

I assume that either the booster or the MC is shot.  Anybody BTDT?
--Gary