Now when I stop at the light, my brake peddle slowly creeps down to the floor and then I start rolling backwards, slowly. I have to pump the peddle one time to keep it still for another session.

What causes this?

 

Usually a bad master cylinder.

 

so do I just go to nappa and pick up a new master cylinder, then?

 

They have good directions in the box. Don't skip the "bench bleed" part either.

If it still does that same thing after you swap the master cylinder, let us know. It'll be the hydraulic control (dump) valve used for the rear ABS.

 

The operative word is "new" not rebuilt. Even a lot of new master cylinders will leak.

 

Yep! I had to replace the one in my car twice with a rebuilt. This one is holding pretty good though.

Edwin