Hissing sound coming from brake pedal

[BLADDERMETAL]

My car has always made a slight hissing sound behind the brake pedal when i would apply the brakes before,it wasnt that loud either you could just hear it. But just recently its making that hissing sound all the time without me even pressing the brake,i noticed it the other day when i had my radio comepletly off. My brakes work the same as they always did,its just very annoying to hear that sound all the time now,sounds like a air hose. Is it a gasket or rubber piece of some sort i have to replace???Im just worried that one day i will press my brakes and they wont work.

 

[timeless2]

Pop the hood and check for any cracked, disconnected, or ruptured vacuum lines near the firewall or perhaps the intake, PCV, or EGR.



Oh, and GTOReturns, keep your senseless posts (I deleted the one you just posted in here) out of Tech sections. Thank you.

 

[tuhockey11]

Its most likely the brake booster diaphram leaking. Mine was doing it whenever I hit the brakes, put in a new one and havent heard it since. However, Im not sure if they get to the point where they leak constantly. How is your pedal feel? If its hard then it is your booster good luck

 

[LiquidGT]

There is a vacuum dump valve right on the brake pedal, dont know what its for, either the valve went bad or the vacuum hose is busted. I seen it when I did my pedal swap.

 

[88mouse]

There is a vacuum dump valve right on the brake pedal, dont know what its for, either the valve went bad or the vacuum hose is busted. I seen it when I did my pedal swap.

Could be the line that Liquitdgt is talking about. Or like someone else said the booster is bad.

The line on the valve goes to the cruise control. When you hit the brakes turn the cruise control off.

 

[Fast63]

Disconnect and plug the vacuum hose going to your power brake booster. If the hissing goes away, then you know it's the power break booster. If it's still there you know it's something else

 

[PUNISHER RACING]

brake booster is bad

 

[BLADDERMETAL]

My car doesn't have cruise control. I havent check my car yet,havent had time.I will follow up and let you know what i find when i get to check things.