Brake Pedal Air Noise ?

[77 Must-Stang]

Hi,
When I start my 77 mustang ll and push the brake pedal in, I get a air leak noise. (in neutral) Its definitely coming from the pedal area. Could this be the Booster or, the Booster diaphragm? Thanks for any help.

 

[MustangIIMatt]

Hi,
When I start my 77 mustang ll and push the brake pedal in, I get a air leak noise. (in neutral) Its definitely coming from the pedal area. Could this be the Booster or, the Booster diaphragm? Thanks for any help.

It's usually the booster.

 

[jozsefsz]

Yeah the booster's shot (diaphragm dried up and leaking severely), they're not too expensive so just change it out. Parts (if you can find them) are usually more expensive than a reman unit, and this type is a hassle to disassemble.

 

[jozsefsz]

It could be your linkage, the booster, or the master cylinder. A creaking noise is most likely the master cylinder. An easy way to eliminate it is to disconnect it from the booster and move it aside (may need to bend the brake lines just a little bit). Press the pedal and see if you still get creaking. If yes, linkage or booster, if no, the master cylinder. If you're fluid hasn't been changed in a very long time, a thorough flush might help if you diagnose it to be the master cylinder.

FYI it's good manners to start your own thread.

 

[77 Must-Stang]

Ya, cheap enough to replace. Rock Auto was best price i found. Thanks for your help !

 

[77 Must-Stang]

Hi
Well, I got my new brake booster and master cylinder. Had the fun of Bench bleeding for the first time. Only wrecked one brake line and got 3 booster nuts out from under the dash. Anyone know the easiest way to get the top right one out? Not much room. Thanks for any help.

 

[jozsefsz]

U-joint and a long socket extension if I recall correctly, it wasn't much fun. I had to use a pretty thin-walled socket too as I remember the brackets made it hard to get to the nut.

 

[77 Must-Stang]

Yup, That was it. Thanks