I have a rather pronounced whistling sound when driving my 95 Z28 auto. At idle, I do not hear it over the engine, but once rolling it becomes noticable. At about 20 mph it becomes virtually constant in volume.

I have no stopping issues with the brakes (other than the fact they are LT1 brakes), but I have noticed that about 5 seconds after turning the car off, the brake pedal has gone hard. Today I turned the car off with the drivers door open and my foot on the brake, and a slight hissing noise could be heard as the pedal went hard.

Is this normal for the brake booster to bleed off vacuum so fast and do you think that it could be the noise I hear?

Thanks for the help in advance.

Mike

 

TTT on this one. I'm experiencing the exact same thing. I also noticed that when pressing the brake all the way down at idle, my idle RPM drops about 2-300 rpms.Are you experiencing that as well?

 

Anyone have an idea on this problem?

 

Seals in the brake booster are bad. Replace the brake booster. That's what mine was. The heat from my header wasted the seals inside the booster bc my header heat shield came off.

 

I see, thanks.