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Seized Brakes, what can I do?

I did again, I bought another 914 "cream puff". First off, it is true, there is no such thing as a "rust free" 914. Next, the brakes on my 75 2.0L are draging really bad. I didn't have time to take them off this weekend but I was wondering what I should do when I get to it.

1. I seem to remember someone saying that to un-seize the brakes I have to "pop" the pistons in there bores. I guess I just compress the pistons with a C-clamp, making sure I don't push the other one out. This might break up the rust seizing the piston. My question is has anyone done this? Does it work or just tear up the seals.

2. Is it the rust on the rotors and pads causing all the draging\heat? Is it just that I have to turn the rotors and change pads (I'm never that lucky).

3. Are these symtoms fatal? can I rebuild the calipers, or do I need new ones (Gulp!)?

Please help, besides the brakes I have the car road worthy (at least in my opinion) and can stand to let the good weather pass me by.
Old 10-25-1998, 04:51 PM
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There are several things that could be causing the brake pistons to stick. And it's not that easy to tell what the problem really is without a significant amount of work.

First of all, you should just try working the pistons in and out. Use a lever of some kind to push the piston in, then use the pedal to push it out again. If it gets easier, you may have fixed your problem. Probably not, though. 8^( But at least it's quick and cheap.

Next possibility is that you have swollen rubber brake lines. Typical failure mode on these pieces is that eventually the hose swells. The VERY high pressure you put on the system with your foot can force fluid into the calipers, the relatively small pressure exerted by the rubber seals trying to straighten out again cannot push the fluid back through the swollen lines. Replace the lines with new rubber ones (hey they lasted 27 years, right?) to fix it. Not sure how else you can tell.

Worst case, neither of those works. Time to take the caliper off and remove the pistons. If there's much pitting on the pistons or bores, it's worth looking around for some used rebuildable calipers. If things clean up well, then just rebuild the calipers and go.

I'd guess that it's probably the brake lines, but if some PO wasn't very good at changing out the fluid, you might wind up needing new calipers.

Good luck!

--DD
Old 10-26-1998, 10:26 AM
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I agree with Dave about the testing and such. I would really flush the brakes (all 4) with ol' two person system so you can see if you get a good flow from the vent screw when the pedal is pumped. Next you can pull the pads and put a piece of wood so they don't pop out of the bore, then push them back in. Listen with a stethscope for any noises on the caliper, should be a whooshing sound from the fluid only. If there is chattering it is sticking pistons probably. If it is just the fronts, may be a good time to do the BMW brake upgrade??? or have rebuilt ones from NAPA or do it yourself with kits. The pads could be jamming as thye should be slightly loose once you pull the pistons back. Check for rust, sharp edges, burrs, etc. I never let our pads get to less than 1/2 original thickness since the heat line from autoxing usually is about 1/2 the pad thickness and I don't want the heat getting to the pistons and fluid.

[This message has been edited by john rogers.]
Old 10-26-1998, 12:05 PM
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Thanks for the advice, too bad I won't have time to get to the car for about two weeks (I allways say that, then end up under my car until 3 a.m.). It has SS brake lines, I still haven't received the history (receits from the last 20 years) from the PO, so I don't know (or trust) how old they are. I've heard that except for "Earls" SS lines, no SS line is D.O.T. approved. Something that they don't give any warning and just GO one day (saw a new Vette blow a new line at Nelson Ledges during a school back in 93, had big brakes and coolers, but still a heavy car).

Anyway at least I know I'm on the right track and I can at least try to save them for the time being.

BTW how far out of the bores can the pistons go so I can look at them? I guess I'll push them out "just" enough to see the sealing area. Also has anyone used the rebuild kits? They make them for the front and rear. The car came with new pads in the box, and a number of other neat new parts (new, in the box, negative "PORSCHE" lettering, COOOOOL). So I guess the brakes were not a new problem.

Oh, and another thing, the fulid was clear, the pedal assembly bushings seem O.K., and the MC dosen't seem to be leaking into the pedal box area. Who knows I might get lucky! NOT!
Old 10-26-1998, 07:28 PM
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