Brakes

[Don Bishop]

Anybody help on a brake problem. the rear brakes on my Vette don't seem to be working correctly, I installed new pads, bled all the brake lines, the front breaks bled easily but the rear brakes still have air bubbles[ Large] coming out, I put enough brake fluid in to bleed 2 cars, anyone have a suggestion where to start?

 

[Yoda]

Don Welcome aboard the CAC..

If you could provide a bit more information e.g. year we can move this into the proper Technical Forum.. We have a lot of members that probably could help you out

Welcome and enjoy the

Bud

 

[Don Bishop]

Rare 81, the corvette with the brake problem is 1978, on the passenger side rear there seems to be 3 bleeder screws, 2 on driver side rear and 1 on each side on front calipers, the front was easy to bleed but the rear calipers are the problem...
thanks Don

 

[81C3]

The rear should only have 2 bleeders and the other so called bleeder port should have a plug as its not a bleed port.
You only need to bleed the rear starting with the inside half of the caliper and then the outside. You might need to get a small rubber mallet and tap on the caliper as you bleed it as it like to trap the air.
If i'm not mistaken i believe it's left rear inner, left rear outer right rear inner, right rear outer, right front then left front.
Good luck

 

[82RL]

On My 82 I can bleed the brakes and they will be rock hard for a couple of months then start to get softer and softer. I can not find any leaks and there doesn't seem to be any fluid missing. any Ideas?

 

[JR-80]

The softeness you get after a while is probably caused by run out in your rotors causing a slight pulse that pumps air into the calipers. The new style o-ring calipers were designed to eliminate this problem.

 

[JR-80]

After a hard 200 mile highway run my brakes got really soft- almost to the floor. A quick gravity bleeding got them back to normal. In a pinch turn your wheels all the way to the right, reach back and loosen the bleeder and let it drain for about a minute or two. The air will be pushed out by gravity. Repeat on the other side. Worked great. Pedal was back to normal. Always carry a can of brake fluid with you. The above method can get you back home.

 

[82RL]

Who has the new style calipers.

 

[JR-80]

www.vettebrakes.com has the piston kits if you already have stainless steel sleaved units or they have the complete calipers

 

[TWINRAY]

I've found the vacumn brake bleeder a good item to have in the toolbox. It costs less than $40. I had an instance when gravity bleeding didn't work . I needed the boost generated with the vacumn.

 

[lobes290]

82-RL I have the same problem, could you please help me out if you corrected you problem, Lobes290@hotmail.com

 

[elseyj]

Twinray is right. I was always a "pump-hold and bleed" guy. After my last rebuild a friend convinced me to try the vacuum bleed. I'm a convert. Much quicker and rock hard pedal.

 

[82RL]

Bled the brakes on the 82 again last night right rear (passenger side had no air)drivers side had a one pretty good size bubble every time the brakes were pumped at least 5 to 10 times. Can any mechanic check the run out on the rotor or is that going to be a corvette mechanic specialty.

 

[81LT4]

To bleed the brake's rite the first time, you must use a vaccum
style pump. $40.00 at your local auto part's. When you bleed
the rear brake's you must plit the vaccum line into two part's
(LIKE A T) CONNECT BOTH LINE'S TO THE BLEEDERS, PUMP THE VACCUM THEN RELEASE THE BLEEDER'S. Keep pumping till the
air is out or the cup is full. Repeat as often needed. that's the problem that most people are not familiar with. I also learned the hard way. as long as there is no fluid leaking from the calipers the pump will work.
GOOD LUCK. AND DON'T FORGET TO BUY EXTRA VACCUM HOSE AND A VACCUM T.

 

[1981]

82RL,

I have the same problem, after a 200 mile highway trip the brake light come on and the pedal goes way past normal, while the car has a hard time stopping. The rear seems to give out, that left rear system gets full of air and I can not bleed it free with the pump and flush method. The same symptoms happen, everytime I pump, more air pushes out of the brake line! Doesn't make since. Have not tried the gravity bleed, will next time.

When the rear system fails the proportioning valve has a ball which then moves and blocks the rear system off from the front, allowing the front system to work without being affected by the failing/leaking rear. I guess that is how it works? Someone correct me if I am wrong. My system has failed (light come on and brake pedal very spongy) many times thiese last months while on long road trips. The brakes still work, my front do anyway, the rear are always lost. I drive the car back home after the trip, try to bleed the brakes myself, and can never get the air out of the left rear. My mechanic knows how, just haven't asked how he does it. I think he uses the vaccum method.

So when I bring it in.
My mechanic tells me, "run out will not cause this problem." He is full of it or too ignorant about these year corvettes. And always tells me, "the air was left in from the last fix" or "the proportioning vavle was stuck, we centered it and it works now". But since he bleeds the brakes for free everytime the light has come on, I do not complain.

Just that the the problem is STILL there, he has only fixed what the problem caused, not the problem itself. Which is what 90% of any work force does when given a problem to solve.

Let me know what you do and if you find something that works. If I find a solution this group will here about. For now, my car drives great, until that next long trip.

1981

 

[Vettehead Mikey]

82RL,

My mechanic tells me, "run out will not cause this problem."
1981

Time to find a new mechanic. One that knows how and why 65-82 Corvette brakes are different than any other GM car.

 

[1981]

Time to find a new mechanic. One that knows how and why 65-82 Corvette brakes are different than any other GM car.

You are right, but that is easier said than done. I hear everyone talk about finding that great mechanic to do fix it jobs on their car. I have not been that lucky to find one in my area. So he is pretty much all I have for this problem.

1981

 

[GTR1999]

If you can't find a good C3 vette mechanic, can you do the work?
If you're able to, you can resolve this on your own with some help. Runout can be repaired at home as long as the rotors are not warped,cracked, or grooved. You'll need a good indicator and some shims but you should be able to get the runout down under .003" with some work. I have to do 2 front rotor this weekend for the same thing. Once you get the runout fixed then you can look at the rest of the system. I don't recall if you changed the brake hose or not? If not replace them, I like the rubber over the SS. The stock lip seals will work fine once the runout is correct, and with ss calipers you should get a long life out of the system. Bleed the brakes once a year if you don't drive the car much.