Hisss sound when braking
Burning Brakes
Joined: Feb 2003
Posts: 1,144
Likes: 18
From: Panhandle FL
Re: Hisss sound when braking (JCAIRE2)
There is a cruze control switch on your pedals (I can't remember if its the brake or clutch) but it is vacum operated.I think it's the clutch,brake has an electric switch.Pull the lower panel that covers the tops of the pedals,stand on your head and you'll see them.I had to check mine when my cruz went out.Sounds like yours is going out. :auto:
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Re: Hisss sound when braking (BlackandMild1)
Brake booster uses vacuum assist. If the brakes hiss when you apply them, you're hearing a vacuum leak from the engine cause the diaphram isn't sealing properly. Need to replace the whole thing.
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Verdad Gallardo
Safety Car
Joined: May 1999
Posts: 3,651
Likes: 5
From: Atlantis
Cruise-In I Veteran
Re: Hisss sound when braking (SPEED750)
I'm with SPEED750 on this one.
The vacumn hose may have come off the cruise interupt switch or the switch may have failed and is letting air enter the vacumn system at the brake switch.
If it's the switch The Last Detail has them for about 9 bux.
The vacumn hose may have come off the cruise interupt switch or the switch may have failed and is letting air enter the vacumn system at the brake switch.
If it's the switch The Last Detail has them for about 9 bux.
Race Director
Joined: Oct 2001
Posts: 19,653
Likes: 428
From: Melbourne Florida
Cruise-In IV Veteran
Re: Hisss sound when braking (BlackandMild1)
Deja Vu all over again...this happened to me at Noon today !...exact same noise...turns out the brake booster died...will be replaced tomorrow...btw, it can be driven but very carefully if at all... :D ...good luck
[Modified by golfboy1, 6:10 PM 3/13/2003]
[Modified by golfboy1, 6:10 PM 3/13/2003]
Pro
Joined: Apr 2002
Posts: 584
Likes: 0
From: Baldwinsville NY
Re: Hisss sound when braking (golfboy1)
How do you "know" the brake booster died? I have had that hissing in my car for years but only when I don't drive it for a few days and then only til the car warms up after a few stops. The thing I have had for a couple of years now is, no matter how hard I press on the brake pedal, I can NOT lock up the tires at all, but the stopping distance seems okay (keep in mind, anti-locks didn't exist in 84). My mechanic said the brakes visually look fine when he checked them last fall. Is it my booster?...any help? :confused:
Drifting
Joined: Feb 2003
Posts: 1,978
Likes: 2
From: San Antonio Texas
Re: Hisss sound when braking (BlackandMild1)
:rolleyes:
Read your question yesterday....got in my car today and darned if mine isn't doing it now too! My pedal was real hard and caught me by surprise!
Big adrenaline rush for a second!!!! I checked the cruise control thingie and it
seemed ok, so I guess It's booster time for me too. Any prices yet?
Thanks
Read your question yesterday....got in my car today and darned if mine isn't doing it now too! My pedal was real hard and caught me by surprise!
Big adrenaline rush for a second!!!! I checked the cruise control thingie and it
seemed ok, so I guess It's booster time for me too. Any prices yet?
Thanks
Race Director
Joined: Oct 2001
Posts: 19,653
Likes: 428
From: Melbourne Florida
Cruise-In IV Veteran
Re: Hisss sound when braking (84number2083)
Sorry... I just saw your post...I know it's the booster because I limped it to the shop and my mechanic checked it...replaced last Friday and all is well...when your booster goes out you'll know it cause you'll hardly have any brakes at all !...the car will stop but it takes a while and a lot of pressure on the pedal...yours may be on the way out but not quite there yet...your choice, but I'd look into it now because hitting the brakes and not stopping is scary...believe me I know... good luck
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Re: Hisss sound when braking (84number2083)
Yes.. with a faulty/leaky brake booster you'll get little or no vacuum assist from the engine..
It'll hurt you in TWO dangerous ways...
Without vacuum assist, you won't get much line pressure, and it will be a pain to get the car to come to a full stop quickly.
Second, the vacuum leak seen by the engine during braking is the worst time for one to occur. Say you're coasting to a stop, then you hit the brakes, the engine suddenly leaks vacuum, so it leans out the motor.. your motor will stumble, your engine will compensate with more fuel which will rev the engine, (very bad for breaking if you're in gear). In some cases, especially in cold weather the vacuum leak will stall the engine and then of course, you lose your power steering.
A functional booster will hold vacuum even if the engine dies, and give you one last puff of assist to help you come to a stop safely.
On my other car, the engine died while cruising down a steep hill and hitting the brakes when I came up on heavy traffic. I lost my power steering, and brake assist. I guess all the curling I did at the gym paid off in that moment. :eek:
It'll hurt you in TWO dangerous ways...
Without vacuum assist, you won't get much line pressure, and it will be a pain to get the car to come to a full stop quickly.
Second, the vacuum leak seen by the engine during braking is the worst time for one to occur. Say you're coasting to a stop, then you hit the brakes, the engine suddenly leaks vacuum, so it leans out the motor.. your motor will stumble, your engine will compensate with more fuel which will rev the engine, (very bad for breaking if you're in gear). In some cases, especially in cold weather the vacuum leak will stall the engine and then of course, you lose your power steering.
A functional booster will hold vacuum even if the engine dies, and give you one last puff of assist to help you come to a stop safely.
On my other car, the engine died while cruising down a steep hill and hitting the brakes when I came up on heavy traffic. I lost my power steering, and brake assist. I guess all the curling I did at the gym paid off in that moment. :eek:
Racer
Joined: Jan 2000
Posts: 378
Likes: 0
From: Lakewood, Colorado, USA
Re: Hisss sound when braking (84number2083)
Had the same problem. Don't drive it until you get it fixed. Contact Jeff at Superior Chevy in KC. Gave me a great deal, about $75 bucks less than the rags charge and was here in three days. His number is 800 728 8267. He is 18carfan on this site. Good guy. Good prices. Understands corvettes. Luck...-C4-
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Re: Hisss sound when braking (Curveit)
I checked on some prices today... $250 at Mid America
$175 Corvette Central... $97 A-Zone. Good luck with
yours.
$175 Corvette Central... $97 A-Zone. Good luck with
yours.
Buy from Jeff Kopp. I've had no personal dealings with him.. but he seems to be the go-to guy here on the forum.
