break issues
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Joined: Jan 2008
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From: Salt Lake City UT
break issues
i have noticed a hissing noise when i use the break peddle to stop and it is very stiff and need to use both feet to press the break to hold the car at the stop. i have not replaced the fluid at this time but plan to do so soon. the car is not a daily driver, so i have time to experiment. i did remove the cap on the fluid cylinder, the fluid looks more like old motor oil....
Race Director
Joined: Oct 2005
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From: Rolla Missouri
2021 C4 of the Year - Unmodified Finalist
St. Jude Donor '10 thru '25
The fluid isn't your problem, although from your description, it needs replacing anyway.
The hissing your hearing is a vacuum leak. Your brakes are power assisted and rely on engine vacuum.
The hissing sound and the extremely hard pedal you feel are classic symptoms of a bad brake booster, or a leak in the vacuum hose between the booster and engine.
The hissing your hearing is a vacuum leak. Your brakes are power assisted and rely on engine vacuum.
The hissing sound and the extremely hard pedal you feel are classic symptoms of a bad brake booster, or a leak in the vacuum hose between the booster and engine.
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Joined: Jan 2008
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From: Salt Lake City UT
i was hoping that would not be the case as i have been checking part pricing. i looks as the car will be in the garage for a time. thanks for the help. the booster is the part bolted to the fire wall?
Race Director
Joined: Oct 2005
Posts: 11,770
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From: Rolla Missouri
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St. Jude Donor '10 thru '25
Yes, and the brake master cylinder bolts to the power booster.
It will look similar to this. The booster is the black drum looking thing the master cylinder is bolted too.
Also note, just to the left of the white plastic reservoir you can see the check valve going into the booster.
Hard to see because it's black also, but you will see a hose going from that back to your engine.
Check the hose and connections for breaks or cracks. You might get lucky and find the connector or hose is just split.
If so, just replace them and you might not have to replace the booster.
It will look similar to this. The booster is the black drum looking thing the master cylinder is bolted too.
Also note, just to the left of the white plastic reservoir you can see the check valve going into the booster.
Hard to see because it's black also, but you will see a hose going from that back to your engine.
Check the hose and connections for breaks or cracks. You might get lucky and find the connector or hose is just split.
If so, just replace them and you might not have to replace the booster.
Burning Brakes
Joined: Aug 2007
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From: Austin Tx
If you are hearing the hissing inside the car the booster diaphram is bad and the booster will have to be replaced. Be sure and check for brake fluid between the master cylinder and the booster. This is a common cause of failure of the diaphram in the booster. If fluid is present you must change the master cylinder as well.
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Joined: Jan 2008
Posts: 69
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From: Salt Lake City UT
no fluid anywhere, just a bad booster. in the replacing of the booster, will adult words be necessary to complete the installation and removal. and do i need to remove part of the dash?
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Burning Brakes
Joined: Aug 2007
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From: Austin Tx
You pulled apart the master cylinder from the booster and checked in between them for fluid?
I haven't changed the booster on a vette so I couldn't tell you how hard it is. I'm sure someone will chime in if you ask. Some cars are easy and some are a royal pain.
I haven't changed the booster on a vette so I couldn't tell you how hard it is. I'm sure someone will chime in if you ask. Some cars are easy and some are a royal pain.
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While you're at it, it's a pedal. You peddle a bike. 
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i went to st. louis public schools.
Coincidentally, the Corvette was manufactured in St. Louis from 1953 to 1981.
Coincidentally, the Corvette was manufactured in St. Louis from 1953 to 1981.
Thread Starter
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Joined: Jan 2008
Posts: 69
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From: Salt Lake City UT
those im good with, but i really did have the surgery. i still have some memory loss issues. im just happy to be veritical and have the ability to drive my car, or at least untill the brake booster situation....
