BRAKE HELP

[wild70stang]

BRAKE HELP Still not revolved

I replaced the brake booster because I was pushing the pedal to the floor. I bled the brakes till there was no more air bubbles coming out. while the car is running (parked) the pedal goes straight to the floor with no resistance. At the same time (while holding the pedal down) the engine shutters as if all the vaccum is gone. The master cylinder is full and squirts each time I press the pedal (the brake booster is adjuste properly to corerct length). please help me!

Any Help is Appreciated!

 

[jcode68]

Did you bench bleed the master cylinder? Even if you didn't seems odd the pedal goes to the floor. if you take the cover off the MC and depress the pedal slooowly, do you see air bubles?

 

[wild70stang]

I dont see air bubbles, the liquid squirts out like a small fountaing (doesnt squirt out of MC). No I did not bench bleed the MC. Should I after replacing the booster? My only concern is the new booster since my car shakes after pressing the pedal while its running. I can bench bleed the MC and rebleed my brakes (I probably didnt get all the air out).

 

[fasttback]

Is your MC new? Sounds like it getting old (slowly leaking past the seals in the MC).

 

[wild70stang]

The MC is rusty on the outside but was working fine before I took the brake booster off. I will bench bleed it tomorrow or possibly replace it. I still wonder what was causing the booster to suck so much vaccum...

 

[gsxrken]

Boosters are notorious for rebuilds not working correctly. "New" doesn't mean "good". Check that it holds vaccum with a mityvac, and/or take an engine vacuum reading to see if drops when a friend pushes in the pedal but does not let off.
But backing up, it sounds like you jumped the gun on the booster. A pedal going to the floor sounds more like a bad M/C, not a booster. You say your M/C was good before you swapped the booster... how do you know that? A bad booster usually means a very firm pedal, not an overly easy one. If you plug your M/C outlets and it still sinks to the floor, it's definately in the M/C and not downstream in the lines or brakes. I would get a new M/C, bench bleed it before you put it in, and go from there. They're cheap.

 

[wild70stang]

Thanks alot, I will try that out.

 

[wild70stang]

Well, I installed the new master cylinder today and that is not the problem. The brake pedal does not return about 50% of the time that I press it. I am stumped as to what is wrong. Im gonna check the vaccum line, and possibly remove the whole dam thing.

 

[bnickel]

was this an original power disc brake car or manual drum? it sounds to me like it was manual drum and someone swapped in the power booster but didn't change the brake pedal, the manual and power brake pedals are very different and not compatible.