Updated 05/01/2002
Rebuilding e12 calipers
E12 calipers are pretty easy to rebuild. Here's a link that will open in a new window to the Senior Six Registry E3 Caliper (which are pretty much the same as e12 calipers) Rebuilding FAQ by Bill Bowes: http://texasconsulate.com/faq/calipers.htm (opens in new window). The Senior Six Registry can be found at http://www.seniorsix.org
Also as the Ate E12 brake calipers are the same as some Ferrari calipers, here's a link (thanks to Peter Claassen) for FAQ of Ferrari Ate calipers http://www.r-design.net/308/techtip2.htm
Some points I must add:
It may be easier to 'ease' the pistons out of the bores (to the limit of their travel) with the calipers still on the car if they are really siezed. By removing the pads you now have up to 1500 psi available via your foot, the brake pedal and master cylinder — assuming the system will hold fluid. To use this method, first remove the pads. Then press the pedal gently once about half way down and then examine the pistons. Some will move out easier than others. Once one of the pistons is near the limit of it's travel (boot stretched), jam a suitably sized piece of wood between that piston and the rotor. Then you can repeat the procdedure, pressing the pedal and blocking the pistons until all four (two for rear) pistons are out. At that point the wood can be removed and the procedure in the SSR Caliper Rebuildling FAQ should finish the job. If the brake fluid has sat unchanged for years, there's a good chance you may need to try this on-the-car method as the fluid forms a kind of varnish around the piston making it really stubborn.
Consider replacing rubber hoses at the same time. I used DOT-rated stainless steel lines (Mesa Performance has good prices) but even the OEM rubber hoses will be fine.
Replacement hard lines can be obtained at NAPA auto parts as well as many other suppliers. You'll need to bend it yourself but the 3/16" tubing will come pre-flared with M10 fitting on each end.
When getting the old rusty hoses and hard lines loose, the Vise Grip 'Nut Buster' 7LW will come in very handy, in addition to hydraulic flare wrenches. Pep Boys Auto Parts has the 7LW pretty cheap.
Get a piece of brass brazing rod and cut it at an angle with wire cutters to form a 'pick' to extract the seals once the pistons are popped out. The brass is softer than steel and won't scratch the pistons or caliper bores. Scratching the pistons or bores is a no-no and a good way to insure a leak.
Use only Ate kits. They don't cost much more than off-brand parts and they will last as long as the orginal seals if you change your brake fluid.
After all this, change your fluid once a year. Not changing the fluid is what got you to this page in the first place.
E12/E3 calipers are very high quality. Just price them compared to newer e28 floating calipers. Take care of them and they'll stop your car well.
When re-installing the calipers, it's easy to get left and right sides reversed; especially the rears. If you do, they won't bleed. All bleed nipples should face up. Thanks to Wietse for this tip.
Start by bleeding the rears then move to the fronts.
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