Where to start...I replaced my master cylinder about 2-3 weeks ago with a brand new one (I had bad luck with the reman) My brakes worked fine until a week ago. I was at my girlfriends house and we went to the store, my brakes worked fine on the way to the store. I come back out and start the car up and didn't have any brakes, the pedal goes to the floor. Anyway I drove it back to her place carefully and looked around my car. I left it for about 15 minutes, came back out and the brakes started working again so I drove it home. The brakes gave way again and so I took it slow. This past weekend, not knowing what it could be I replaced both my calipers with remans, both rear wheel cylinders and the front rubber lines. The brakes still are not functioning.
The brake lines were bled correctly and so was the master. Does ANYBODY have any suggestions?? :confused:
Sorry for the long post, but I wanted it to be accurate and detailed enough.

That sounds like another bad master cylinder.

You said you bench bleed the MC right? Try bleeding the MC again and rebleed the brakes. It sounds like you have air in the lines still.

Joe