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Frozen caliper. Rebuilding and replacing questions.

PostPosted: Sun Feb 13, 2005 10:23 pm
by Brett 78 911SC
One of the pistons on one of my SC's front calipers is frozen. It won't push in with the usual force from a screwdriver levered against the rotor. The caliper was dragging on the rotor before I started taking things apart.

I was going to rebuild the calipers myself, but with the frozen piston, I'm not comfortable dealing with it. This would be my first time rebuilding a brake caliper. If it's corroded inside, for example, I wouldn't know how to deal with it properly.

I have found Vertex Auto online for a source of rebuilt calipers. Are there other sources? Anyone local for rebuilt calipers? Also, is a frozen caliper still viable for core exchange?

Thanks for your help,
Brett

PostPosted: Mon Feb 14, 2005 1:30 pm
by richard
If you were willing to attack a rebuild yourself before you discovered one was frozen then I wouldnt let that stop you unless they are really frozen, which if you have been driving the car I doubt. Most "corrosion" can be cleaned up with very fine "sand" paper. Worse case is you trot your parts over to your friendly mechanic and let him finish up the job, but you will have learned. The worst part of the job is the mess, if you do it like I do, which is to pop one cylinder out at a time by removing one pad and pumping the pedal. I get brake fluid all over the caliper and the floor. I then remove the caliper to clean up the "corrosion". But you need to plug the brake line to the caliper or fluid will continue to flow out, which drains the reservoir, which allows air into the system, etc. Bleed the system...and start over on the next cylinder.

PostPosted: Mon Feb 14, 2005 6:37 pm
by ttweed
richard wrote:you need to plug the brake line to the caliper or fluid will continue to flow out
Here's a tip-- if you depress the brake pedal slightly, just enough so that the piston in the master cylinder covers the supply port from the reservoir, but not enough to build up a lot of pressure in the system, and "stake" the pedal in this position, it will not continue to bleed fluid when you disconnect the brake line at the caliper.

Are you sure your piston in the caliper is seized and not cocked? Try a C-clamp on it instead of a screwdriver. It is likely to be very rebuildable still, unless the pistons are highly corroded. I don't know how much Vertex is charging for rebuilt calipers, but you can buy a brand new SC or Carrera caliper for about $200 ea. Buy new ones, and sell your old cores to someone and you may come out ahead on the deal, since you will have brand new brakes then instead of rebuilt ones.

If you're going to rebuild them yourself, you might find this page at Pelican Parts helpful.

TT

Thanks for your responses. I think I will go with new ones.

PostPosted: Tue Feb 15, 2005 9:21 am
by Brett 78 911SC
I've been mulling this over for a couple of days. I intend to keep this car a long, long time, so I think I'll start fresh now with new calipers. They may be perfectly rebuildable, but I would rather know the full history of the parts on the car from new. I'll get my rebuild experience when the new ones are a few years old.

Thanks,
Brett