Brakes: What does a brief ptsss sound mean just after I step on the pedal?

[IronWing]

The brakes on my Olds are making a momentary ptsssss sound just after I press the pedal. It usually doesn't happen when I first step on the brakes after cruising for awhile but does on subsequent pressings of the pedal. The sound is a bit like an air brake and only lasts a moment. The brakes feel fine and work well.

 

[Bignate603]

Sounds like something with your brake booster. You may want to open the hood, run the car and have somebody step on and off the brake to see if you can hear the hiss at the brake booster. It might be starting to die. Brakes are one of those things where I don't really want to wait until something fails before I fix it. If the brake booster dies though you can still stop, it will just take quite a bit more pressure on the pedal. While not as dangerous as completely losing the brakes, you can easily rear end somebody if the brakes suddenly need 5x more pressure on the pedal to stop your car.

 

[Meghan54]

Sounds like the brake sound I've heard on almost every GM vehicle made from the 1970's through the 1990's.....almost all GM's made that sound when you applied your brakes.

But, what year and model is your Olds? Is your braking distance increasing? Is your brake warning light on?

Personally, there's probably nothing wrong at all....but if you're worried, go get them checked out. But I'd be willing to bet an honest garage/mechanic won't find anything wrong.

 

[DivideBYZero]

It's the sound that some brake systems make.

 

[Taejin]

check for gas leaks in your rear

 

[Bignate603]

check for gas leaks in your rear

Rear of the car or rear of the driver?

 

[Bartman39]

I think he means the driver... If so buy one of those little air fresheners that hang from the rear view mirror... :hmm:


As for the air sound as most have said its pretty common with GM cars and trucks to some degree... What you dont want to hear is a constant air sound which means the brake booster has ruptured and is leaking and could completely fail which means a very hard to push brake pedal not a total loss of brakes but damn hard to work with...

I would be really surprised if the truck in my sig ever did it though... It has whats called Hydroboost brakes which is the power steering pump provides the assist pressure for the brakes and the steering so if I lost the pump I would lose both but its not as bad as it sounds and the system is quite reliable anyhow... (knocks on wood :biggrin

 

[CrimsonWolf]

I think he means the driver... If so buy one of those little air fresheners that hang from the rear view mirror... :hmm:


As for the air sound as most have said its pretty common with GM cars and trucks to some degree... What you dont want to hear is a constant air sound which means the brake booster has ruptured and is leaking and could completely fail which means a very hard to push brake pedal not a total loss of brakes but damn hard to work with...

I would be really surprised if the truck in my sig ever did it though... It has whats called Hydroboost brakes which is the power steering pump provides the assist pressure for the brakes and the steering so if I lost the pump I would lose both but its not as bad as it sounds and the system is quite reliable anyhow... (knocks on wood :biggrin

lol at "Overclocked"

Yeah, my Dad's 1997 Grand Prix did this too now that you mention it. We didn't think anything of it. Brakes were always fine. (Though the engine, transmission, power windows, and A/C on the other hand...)

 

[SparkyJJO]

Don't all brake systems make a little bit of a noise like that? Seems like most brake pedals I step on cause a slight hiss noise. <shrug>