Intermittent Brake Issues

[qhunt82]

I have an 03 Dodge 5.7L Hemi. I have been having brake issues for awhile but because its not my daily driver, I havent nailed the problem down yet. It started with a Brake light on the dash and I didnt notice any actual symptoms for awhile. Then one day, I was driving and I went to push the brake and it went all the way to the floor. I immediately let off and pushed the brake again and suddenly it was working fine. I managed to get home with no issues. Shortly after this, I replaced the master cylinder, which has a built in sensor. The sensor had tested bad so I changed the whole master cylinder out thinking this would fix both the light on the dash and the pedal going to the floor that one time. Well, it did correct the brake light. I am still having a problem with the pedal going to the floor but it is very intermittent. It doesnt sink to the floor when I am sitting at a light. It happens randomly when I go to slow down. And every single time, I have been able to let off and re-brake and the problem seems to vanish for awhile. It also does not do it every time I drive the vehicle. I have managed to go 50 miles without the issue. Sometimes it happens when I am reversing out of my driveway. There seems to be no rhyme or rhythm to the issue whatsoever. I have replaced all calipers, pads, and master cylinder. I bench bled the master cylinder before installing and bled the brakes a few times afterwards. Then when I noticed I still had this intermittent issue, I bled the master cylinder while installed, then bled the brakes again. Happened again....so I repeated. Still having issues. Now I am debating on whether or not I got a defective master cylinder. I also tested the booster by pumping the brakes with engine off and starting car. Pedal went down when vehicle was started. Then I removed the check valve and blew/sucked and its good as well. Hose from booster to intake has been replaced and is in good shape and connected. Not sure what to do now. Any advise is appreciated.