Brake Problem

[Jeff Stevens <JStevens@umeme.maine.edu>]

Having some problems with my brakes on my '89 VW Fox.  Not an Audi, but I
thought someone might be able to provide some insight.
Occasionally the brakes totally lock up. This is not a caliper issue. It's
like, I press on the brake pedal only slightly and the pedal automatically
(for some reason) hits the floor. Like there is some sort of negative
pressure. Well, the brakes lock up and the car needs to be shut off (or the
brakes pumped) for the pressure to be released. Anyone have any idea what
this is? It's like as soon as I touch the pedal, a switch is turned on that
collapses the brake pedal. Not fun if you are traveling faster than 5 mi /
h! It seems like a hydraulic thing -- like the brake cylinder compresses
without me even pressing on the pedal. I BARELY touch the pedal and it locks
up and I come screaming to a halt -- and stays locked up. I guess the brakes
work a little too well. Taking it to the VW guy in town later this week but
I thought someone here might have any ideas? They would be greatly
appreciated!

Jeff