My '68 El Camino has SSBC discs up front and stock drums in the back with an adjustable proportioning valve. If I hit the brakes hard and fast, there is a squeaking sound. IT is not affected by speed, it can happen sitting still. If I'm in park and just jab the brake pedal hard and fast, it will do it. I used to think it was something to do with the booster, but it still does it with my new Hydroboost setup. It sounds kind of like a high pressure air or fluid leak, even though I have no leaks. This is why I thought the proportioning valve might make the noise when limiting the pressure to the rear. It does not seem to affect brake performance.

Any ideas?

Anybody? Not having much luck getting replies lately... :(

Greg,
I don't think your lack of responses is your fault. I just think no one has ever heard a prop. valve squeak before :confused:

Joe

Well, that's why I'm asking. It could be something else, the prop valve was just a guess. I wonder what it is???

Do you have poly bushings?

Joe

PST poly graphite. However, this noise will occur when sitting still in park. It is definitely related to the brakes. I guess I'll have to get somebody else to hit the brakes while I stick my head under the hood smile.gif