[rbarton]

Hello, I have a non-Porsche brake problem that has been driving me nuts. The vehicle is a '94 Suburban 2wd with 4-wheel ABS. The issue is that the truck always stops fine, but the firmness of the pedal varies and about 50% of the time when sitting at a stop, the pedal will slowly sink toward the floor. If stopped at a light long enough, the pedal will go all the way to the floor and turn on the brake idiot light. Every time it does it reminds me that my wife says I'm an idiot for driving this thing.

Sounds like a fluid leak, right?? So I've replaced the rear wheel cylinders (one did look like it had been leaking at some point) and the front calipers. I've replaced the seals/grommets between the master cylinder and fluid reservoir and also the diaphragm in the reservoir cap. I've inspected and re-inspected the soft and hard lines. I've bled and rebled and finally paid the dealer to bleed the brakes to make sure all the air is out of the system. The master cylinder and booster were replaced when I bought the truck in an attempt to fix this problem as well. Now about all that I haven't messed with is the ABS controller, a huge contraption that both lines from the master cylinder go into and from which the individual lines come out of. In between I have no idea what this thing does. Could it be the source of my problem? Anything else I should check?

Thanks in advance for any help!!