brake fade

[82RL]

About every 800 miles I have to re-bleed the brakes on the 82. I can't find any leaks or have to replace any fluid. I bleed them and the brake peddle seems very strong. then gradually you can tell they get a little softer till the brake warning light comes on,
Pump it a couple of times and it goes off. Any ideas? Thanks

 

[vmrod]

Are you seeing air bubbles whenever you bleed the brakes? I've heard that C3 brake calipers are prone to develop slight air leaks around the seals. (Especially if your rotors are in need of conditioning.)

If you get air bubbles in when you bleed the calipers, then you may want 1.) to have the rotors turned. 2.) Get the calipers rebuilt. (Mine have been rebuilt with S.S. sleeves and o-ring piston technology, like the 2000 vettes) Either one of these may do the trick, but I would do both, and have no more brake probs!

If you do not see air bubbles when you bleed the brakes, then it could be your master cylinder going bad.

I'm not a mechanic, but I do a good bit of car-work myself.

-Vic

 

[Bob Chadwick]

Another possibility is rotor runout. If not within spec, they can cause the brakes to suck air in around the calipers, particularly if you have the old style seals.

 

[JohnZ]

When you bleed it, do you find most of the air in the rear calipers (as opposed to the front)? If so, that's a classic symptom of either excessive lateral runout in the rotors (especially if they've been replaced), or excessive play in the rear spindle bearings.

 

[Steve Grodin]

John Z is correct. I would also add that if rotors have EXCESSIVE runout the o ring pistons will not correct the situation.

 

[drduckster]

I was bleeding about once every three months on my 76, the brake line (rubber line on the left rear) collasped and I replaced all 4. I have not had to bleed mine since. I was also told to change to a silicone brake fluid, and this would help. btw, the line that I had problems with looked good on the outside, was allowing fluid in but not out...... I thought the car was going to catch fire before I could get it stopped! also check close on bleeding.......some of the calipers have 2 bleeder screws. my .02 maybe this will help.