Solved Brake system help, please

[frankcal]

I'm having a problem with my brake system that I need help with. 2003 explorer sport 2wd with cruise control

So today I just rebuilt both front calipers because they were sticking, and put new brake pads and resurfaced the rotors. Also replaced the master cylinder because its been leaking in the back were it connects to the brake booster. I had been driving with it like that for a while with no issues.

After rebuilding the calipers and installing the master cylinder I'm not getting any brake pressure. I bled the whole system from back to front and also by bleeding the lines that connect to the master cylinder. I have brakes when the car is off, but when I turn it on the brakes go to the floor. I did some searching and read that it could either be a bad master cylinder, bad brake booster or air in the abs module. Is there any way I can determine which one is causing the issue. I replaced the oem master cylinder with a reman a-1 cardone and read that those could be bad out of the box but I don't know. I properly bench bled it and all the lines connect snug to it. It just seems strange to me because when the engine is off I get good firm brakes but to the floor when its running.

I just installed the master without adjusting the push rod in the brake booster, should I have done anything with it? I read that sometimes it has to be adjusted, but I dont want to mess thing ups any further. I also checked all the brake lines and there is no leaks anywhere. I bled the whole brake system twice, starting with the lines that connect to the mc then each individual brake, am I doing something wrong?

I really hope to get this fixed, and appreciate anybody's suggestions

 

[arco777]

When I did a disc rear axle swap, I had a similar issue. Firm pedal with engine off, hit the floor with engine running. I had changed the master cylinder for an A1 Cardone reman unit. Doubt yours is bad. My problem was my stock bleeder screws. They were leaking around the threads and there was so much air in the system they didn't want to work right anyways. Switched them all out for Dorman Speed Bleeders. All of a sudden it worked great and I was able to bleed all the air (there was a lot) out by myself. Just a thought.

 

[frankcal]

Thanks for the reply, I was able to solve it yesterday though. For me it was the cardone master cylinder that was bad. It was leaking from where the reservoir tank goes on and a small small amount from the where it attaches to the brake booster. I went to oreillys and got a new brakebest one. Installed it and bled the whole system once again and worked perfectly fine.

I did have an issue withe bleeders too though a little bit ago, only the two front were bad but just changed all of them with brakebest ones since they were a buck a piece.