CRAZY brake problem

[richduty455]

So as yous know the cheapo beater mark is still not on the road due to brakes....or should I say there lack of....the pedal is very soft and goes to the floor.....I tried 2 new masters and multiple bleedings I also put a new valve in the booster....now yesterday the strangest thing happened......i had the car running and my foot on the brake....pedal was almost to the floor.....i shut the engine off (foot still on the pedal) and the pedal pushes me foot all the way to about a half way up.....whats up with that??? Anyone has ANY idea??? I'm lost on this one

 

[kustomizingkid]

Sounds like a booster thing if shutting the engine off changes things....

Also when you bled the brakes did you bleed the ABS module?

 

[4.6powa]

thats just how it is in any normal brake system... the booster helps with vacuum, shut the engine off, and the booster is useless... takes more effort to push...

anyway...

was the master bench bled?

 

[richduty455]

Yes, the master was bench bled......as for the pedal...its weird it pushes up like that....none of the other marks do it.....

 

[Blenderhead]

If it pushes up, that probably means that the booster is leaking. It is supposed to hold vacuum so that even if the engine is shut off, you should still get 2 or 3 power assists before the pedal is too hard. Try starting the car and not touching the brakes, then turn the car off and wait about 30 secs and hit the brake with the car off. If you get no power assist, then your booster is leaking.