"wooshing" noise while pressing on brake pedal

[grubsster]

Hi all,

I am currently wondering what could be causing a "wooshing" noise as I press on the brake pedal. My brakes seem to function well. Front disc / Rear drum with proportioning valve. There are times that it does not make the noise, but lately pretty much hear it all the time. I'm thinking a bad booster but, don't want to break out the parts gun.

thanks for any advice.

[Dead Parrot]

Assuming vacuum booster power brakes, it is normal for there to be enough vacuum after shutdown for a few pushes of the brake peddle. Without any engine noise, a 'whoosh' is normal as vacuum is 'used up' when the peddle is pushed. Once the stored vacuum is gone, no more whoosh and the peddle gets much harder to push to apply brakes.

On a good booster, the vacuum can remain for many days. One of the early signs of booster failure is that it won't hold vacuum very long.

[grubsster]

Thanks. Never noticed it before. I thought I had a bad master cylinder because my pedal was going to the floor. Ended up both rear wheel cylinders were bad. One was leaking and the other was not functioning. Replaced those put all new brakes on, bled, and brakes work better than ever. Just hearing that noise which is the whole time I'm pressing the pedal. But if it's normal I'm good, just didn't hear it before.

[SCOTI]

I had this happen on my 74 once upon a time. It can happen when there's a seal issue on the booster diaphragm. If the brake power assist functions ok, it's no big deal. But if it's annoying you, you can always replace the booster w/a fresh part.