1982 Corvette Brake System
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Joined: Jul 2019
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1982 Corvette Brake System
So around a week ago my brakes went out while I was driving. Now I had enough, but very little brake pressure to stop the car and get it home no problem as I was not too far away. When I got it back home I tested the brakes with the car off and they where pretty firm but if I pressed hard enough they would go to the floor. If I have the car on, the brake just sinks to the floor. I've checked for leaks on all 4 tires and extensively underneath the car as well and I found nothing as well as I checked if I had enough fluid. The fluid needs to be changed but I had some in there. I tested to see if there where air bubbles in the system by having the cap off of the master cylinder, and the fluid went up when I pushed the brake in and down when I let it out, I do have power brakes all around since it's an 82 and there is a brake booster/diaphragm that is connected to the master cylinder and both are factory.
Any help is much appreciated. Thanks/
Any help is much appreciated. Thanks/
Safety Car
Joined: Nov 2005
Posts: 3,532
Likes: 1,185
From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
Without knowing anything else, it sounds like your brake booster may have gone south. Good luck on your brake issue. 
Last edited by Buccaneer; Aug 20, 2019 at 04:47 PM.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
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From: Cool Northern Michigan
The Booster is strictly an assist. It allows a tender foot driver to lock up all fours with his / her little toe if he / she so desires. The booster has little to do with a brake pedal to the floor. That is a mechanical issue, not vacuum assist issue.
Starting with the Master, unhook both brakelines at the MC. You will have to fabricate a plug for both ports. The ports on the MC are not only different dia, but different thread pitch. Do Not use a bolt for a plug. You will damage the flare inside the port.
You can buy short lengths of brakeline with the brass fittings on the end with the correct dia & TPI to plug off the MC.
Figure out a way to close off the "test-line" ends and install into the MC. (save those steel test lines for bench bleeding another day)
Now you have isolated the MC from the rest of the brake system. Stand on the brake pedal. What does it do? Pass or fail?
Starting with the Master, unhook both brakelines at the MC. You will have to fabricate a plug for both ports. The ports on the MC are not only different dia, but different thread pitch. Do Not use a bolt for a plug. You will damage the flare inside the port.
You can buy short lengths of brakeline with the brass fittings on the end with the correct dia & TPI to plug off the MC.
Figure out a way to close off the "test-line" ends and install into the MC. (save those steel test lines for bench bleeding another day)
Now you have isolated the MC from the rest of the brake system. Stand on the brake pedal. What does it do? Pass or fail?
Last edited by HeadsU.P.; Aug 20, 2019 at 05:41 PM.
Safety Car
Joined: Dec 2012
Posts: 3,797
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From: Summerville SC
Agree that the bad booster will only make it harder for you to stop the car, as in no power brakes. But if the booster has a leak, it will also let air in. Look for fluid behind your speedo/tach are. If your rotors are not true they can actually start moving the brake pistons in and out a tiny bit (pulsate) and I have seen where they can act like a small air pump. You get a little air in one end of the caliper and you won't see it by pumping the pedal. Bleeding each one, starting with the furtherst away from the master cylinder. And do all of the bleeders, each half of the caliper has them. Some people only do one of the bleeders. Good luck and it's probably not prudent to take it out again until you find the problem. Good luck.
Le Mans Master
Joined: Oct 2007
Posts: 7,445
Likes: 970
From: Tennessee/Rhode Island
I agree with those that think it is more plausibly a MC issue. As headsup said, if you can isolate the MC and the pedal goes to the floor, it is the MC.
Most of the time, if you have a dead pedal going to the floor with no leaks, MC. My experience on most cars and my C3 is that air in the system will give a soft pedal but generally will not go to the floor just with air only but usually a leak as well.....
Most of the time, if you have a dead pedal going to the floor with no leaks, MC. My experience on most cars and my C3 is that air in the system will give a soft pedal but generally will not go to the floor just with air only but usually a leak as well.....
