Brake Master Cylinder and changing it ???

I believe I have a problem with the master cylinder of a 1995 Saturn SW2
....
The brake pedal goes almost to the floor when I brake during driving.
With the engine off, the brakes pump up 'ok' ...
When I then start the engine (with pressure still on the pedal), the
pedal goes almost to the floor. The car has ABS.
Neither the service light nor the ABS light comes on ... although the
ABS light came on a couple of times a few weeks ago before I had a brake
peddle problem.

I found a rebuild master cylinder ... the problem is that I have never
changed a master cylinder on a car with ABS ... Anyone have any
suggestions or comments?
Bob

 

I appreciate the note. I have not started anything yet. I may see if I
can get it to autozone ... I have to check what their status is on Sunday.
Thanks!

 

Thanks much for your suggestions ... I was thinking about removing the
battery!
Also appreciate the positive attitude.

 

I found a rebuild master cylinder ... the problem is that I have never

Just curious, what makes you think its a master cylinder instead of, say, a
split brake line?

In Feb, the brake pedal went to the floor in my fathers old ride(92 LeSabre).
Upon inspection I found that the inside of the right front tire was covered in
brake fluid. I pulled the tire and found that the rubber hose running from the
steel hose near the frame to the caliper itself had dry rotted and split
through. Earlier this month, he told me the pedal went to the floor again, and
I guessed it was probably the right side rubber hose........sure enough.

I would check the brake system over before you change the master cylinder.

 

I have not done a thorough check ... haven't had access to a ramp or
lift yet; but it apparently has not leaked any brake fluid ... the
reservoir if full.

 

Ah ok. A buddy of mine's chevy had a bad master cylinder. You'd be driving the
car and all of a sudden the brake pedal would go to the floor.......fun fun
fun. But it could be fixed by pumping the brakes.