[MC06A]

Just recently replaced all brake pads, rotors, and rear brake calipers. When I start the car, the brake pedal gets pretty firm when I pump it, but once I put it in Drive, the brake pedal gets soft and almost goes all the way to the floor. I do have some braking power, but very little. I bled the brakes, but they probably could have been bled A LOT better.

I had the brake master cylinder replaced a little under a year ago, but could it have already failed? Or would getting a much better brake bleed solve the problem? I have a hunch that the former would be the problem. Did I just answer my own question? :surrender:

 

[MC06A]

I just went back out and tested it. With the car off, I can pump the brakes and it gets pretty firm, but it does slowly sink to the floor as I apply pressure. When I start the car, it becomes soft and pumping the brakes does not do anything.

Come to think of it, the pedal was very soft and went to the floor before I replaced everything. It began sometime in mid February and has been sitting ever since then. So, the master cylinder is mostly likely the problem?

 

[MC06A]

That is a classic description of a failed master cylinder.

Or, erectile dysfunction. Take your pick.

Haha, touche, good sir.

I forgot to add/edit something to the last post. With the engine off, I can pump the brakes and hold pressure on the pedal. While it does slowly sink, it only goes about halfway to the floor. If that makes any difference at all.

Should I go get the brake fluid flushed (I think I'm overdue on that anyway) and see if that will fix it, or should I just get the master cylinder replaced at the same time as the fluid flush?

 

[MC06A]

Well, I bled the brakes again yesterday morning. Had my little brother help me out and it became substantially better, although, not what it should be so I took it to the shop. They found a leak from the right front brake hose to the caliper. The threads on the caliper are almost stripped. I guess this is causing air to come into the lines. Ordered a new one and should be here Tuesday and will take it back to the shop. This should fix the problem.