Noticed it the other day for the first time now it is constant. The sound is almost like a constant hissing sound. The thing is it only happens when traveling above 65 mph or so. Top up or down makes no difference. I noticed when I press the brakes it goes away. And comes back once i accelerate again. Could it be braked related? I'm certain it's not a wheel bearing issue, just don't know what to do. My car is an 05 and has 41k miles fwiw..any ideas? Thanks guys!

 

sounds like a vacuum leak through your brake booster? do you have to push the brake pedal harder than usual?

 

I've noticed lately I've had to depress the pedal a little harder..just assumed it was time for new pads.. Would a vacuum leak only make noise at highway speeds? Is this a common problem/easy diagnosis + fix?

 

i hear that too on my car!!!!!!!!! i cant figure out what it is.

 

Gonna change pads fluid and lines and see what happens...needed to do this anyways.

 

its a vacuum leak...changing the pads and fluid isnt going to stop the hissing sound

 

Checked the hoses..they seemed fine..should i just replace the brake booster vacuum hose?