[Guest]

'94 LT1 Caprice, front disc rear drum.

I was coming home from dinner a few weeks ago when suddenly I thought my wheel was going to fall off. The front passenger side caliper was locking up on me. I discovered this after I got home and it was smoking.

I have lifetime warranty calipers on it, so I took the old ones off and went down to AutoZone and got 2 new ones. I figured that would be it, so I replaced them, and to my disappointment, the problem was still there. After driving for a bit, the passenger side front caliper starts grabbing and not releasing.

So I thought maybe it was the rubber hose that goes from the hard line to the caliper. Replaced that, still no dice. Brake still locks up after driving for a short distance.

Then I figured it was the (non functioning) ABS pump doing something to it. So I got a bunch of brass fittings and my friend and I removed the ABS unit, thinking this would cure the problem.

To my extreme disappointment, again this did nothing.

We discovered though that once the brake starts "seizing" for lack of a better word, if I pull over and crack open the bleeder, it will release the pressure and un-seize the brake. But it will still start seizing after a short distance.

I don't believe it's the master cylinder, as it would, especially after removing the ABS, not effect only one side. What else is left? Could the hard line have randomly gone bad? It's like it's allowing pressure to flow forward to the caliper no problem, but only letting a small amount back.

I've tried my theories out and they've all failed. Next would probably be replacing the hard line, which I would like to avoid if possible, but with my luck thus far it seems inevitable to replace it. Could that be what's screwing me here?

I just want to be able to drive my car more than a mile without having to pull over and bleed the passenger side caliper

 

[Guest]

I would suspect the MC, or the combination valve...As strange as you issue is, thats all thats left by the sounds of what you have done already.

 

[Guest]

Sounds to me like you have a dent or kink in the hard line. Your MC has enough pressure (master cylinders make a LOT of pressure) to push fluid past the obstruction, but your caliper doesn't have enough to push it back. So, that's when you crack the bleeder, and *poof* unstuck caliper. I'd inspect all your hard lines thoroughly, taking each one apart and blowing through them. If they all check out clear, disassemble the combi valve to see if you have a piece of o-ring or something stuck in there. Best of luck to you.

 

[Guest]

Well, changed the line for a new one, and said **** it and put another caliper on it.

I'm convinced now, something is acting like a one way valve for the brakes. Would a bad master cylinder do that?

Do the combi valves go bad at all? It's only 64 bucks or whatever to get one but if it's only the master cylinder....well then it's only the master.

Any ideas now? I can bleed the brakes (either side) and drive a long time, and then if I start using the brakes they start clamping up.