Brake problem

My brother has a 95 Grand Prix that just lost the brakes. The brake pedal goes to the floor when pressed. Pumping the pedal does not firm it up. There are no obvious fluid leaks so I am assuming the Master Cylinder is shot. The ABS controller is mounted to the MC. The Hayes manual says that there are components of the ABS that need specific adjustments if they are removed. Should I attempt to change the MC myself or take it to a dealer?

master cyl is easy to change i would do it myself. after you get it bench bleed it before installing. and you should have a bench bleeding kit that comes with the new master cyl. if you take it to dealer there going to rape you..good luck.

I know you said that you did not see any leaks. Did you check the brake fluid level. If the fluid is not low it is the master cylinder. Remember that you have to prime the master cylinder before you install the brake lines. Installing the master cylinder should not be a problem.

Thanks for the votes of confidence. I've changed a few master cylinders in the past. My concern is the ABS valve assembly that is attached to the MC. There are no external lines from the MC to the ABS valve. So that tells me that there must be a gasket of some sort and possibly some internal components that could be misaligned on reassembly. I could always reassemble it with RTV instead of a gasket. Could the manual be right on this particular caution? I've seen many such cautions and have usually found a way around them, but I don't want to jeapordize the safety of the brake system. Has anyone changed the MC in such a system without having any adverse effects on the ABS system?

I have chane quite a few master cylinders, but I have not changed any with ABS brake systems.

We flushed the system this weekend and now he has a pedal. The fluid looked like coffee.