Weak Brakes
Thread Starter
Cruising
Joined: Jan 2009
Posts: 12
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Weak Brakes
Need some help, I recently purchased a 1986 C4 that has sat for the last 7 years. I have a whole host of things that I need to fix but the problem at hand is weak breaks. I have bled and replaced the brake fluid. I have clean fluid at each caliper. When you depress the break it is firm but you can hear air inside the car when you depress the pedal. I did not hear anything near the master cylinder though when depressing the brake. I also did not find any vacuum leaks. Any ideas out there?
Corvette Enthusiast
Joined: Oct 2007
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From: So. Cal.
2025 C7 of the Year Finalist- Unmodified
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brakes
Check power booster for leaks or cracks. Check vacuum line to it also.
Thread Starter
Cruising
Joined: Jan 2009
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I did that but no luck, the large line that attaches to the front top of the power booster could be a little tighter but I dont think its leaking. Is it possible to have the air/vacum leak on the inside of the car?
Corvette Enthusiast
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From: So. Cal.
2025 C7 of the Year Finalist- Unmodified
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vette
Not sure. But is there a vacuum line to control heat AC controls inside?
Le Mans Master
Joined: Jul 2007
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From: Tampa Florida
RF
RR
LR
LF
A little brake booster woosh is normal inside with heavy/quick pedal pressure. Is the pedal really hard to depress and the car won't slow quickly?
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Max G’s
Joined: Nov 2008
Posts: 2,751
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From: Monroe OH
NCM Sinkhole Donor
One other thing. Make sure you do NOT use silicone brake fluid in your brake system. If your pedal is very firm and hard to push, you do have a master cylinder beginning to go bad.
Thread Starter
Cruising
Joined: Jan 2009
Posts: 12
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I used Dot 4 fluid but the pedal isnt difficult to push. If I compare the feel to other cars that I have and have driven it is about the same. The only difference is how poorly the car wants to stop. I am leaning twards something wrong with the booster. I will look at the check valve first and see if it is working. Do the boosters themselves go bad very often?
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
I used Dot 4 fluid but the pedal isnt difficult to push. If I compare the feel to other cars that I have and have driven it is about the same. The only difference is how poorly the car wants to stop. I am leaning twards something wrong with the booster. I will look at the check valve first and see if it is working. Do the boosters themselves go bad very often?
Max G’s
Joined: Nov 2008
Posts: 2,751
Likes: 79
From: Monroe OH
NCM Sinkhole Donor
I used Dot 4 fluid but the pedal isnt difficult to push. If I compare the feel to other cars that I have and have driven it is about the same. The only difference is how poorly the car wants to stop. I am leaning twards something wrong with the booster. I will look at the check valve first and see if it is working. Do the boosters themselves go bad very often?
Safety Car
Joined: Jul 2004
Posts: 3,845
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a link for you........
http://forums.corvetteforum.com/c4-t...n-finally.html
...this deals with a few problems in addition to what the original poster posted about...
http://forums.corvetteforum.com/c4-t...n-finally.html
...this deals with a few problems in addition to what the original poster posted about...
Safety Car
Joined: May 2007
Posts: 3,651
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From: Apple Valley MN
The check valve is the little plastic doohickey on the booster that the vacuum line attaches to. It just pushes into a grommet on the booster. They only cost a few bucks to replace if they go bad.
