lost the donut
 

ok, you know that black donut the goes in between the 2 halves of the front brakes? it rolled away to a place that i cannot find. slap me now i know, but i cut a very thin part of silicone hose to replace it. i really need ideas, i know this wont hold up once they get hot or withstand the fluid. where can i get something like this, or do you think this will amazingly work :-(

No, I don't know about that donut shaped gasket, because in the FSM it expressly states to never separate the caliper halves. It's a static seal, so there really isn't much point in taking it apart.

O-rings are designed and made with precise sizing so that they will seal through a broad range of temperature and pressure. You cannot make one by hand. You could in theory measure the o-ring grooves in the caliper housings and pick a suitable o-ring, but that would be more risky and difficult than getting another caliper.

I think you should buy another caliper. Used, for cost sake.

I'm going to have these calipers for sale soon if you want some nice polished ones:
https://www.rx7club.com/attachment.p...hmentid=176683

Even if you found the gasket, I doubt you'd get a good leak-free seal. Like Dave said, you're not supposed to separate the caliper halves. Get a good used caliper to replace it - NEVER try and half-ass anything with regards to brakes, that's a huge safety issue. Not to mention a leaky caliper flings paint-eating brake fluid everywhere!

Dale

Jeez! Yes you can rebuild the callipers its no big deal and the gasket should simply be a buna o-ring which is simply there to seal the crossover port. in order to do a propper caliper rebuild pop the pistons out with a blow gun pull the old pistion seals and replace them with new oem seals use a slurry of syl-glide(NAPA) and brake fluid to coat all of the rubber bits...the key is to get everything nice and clean before installing the new seals...if there is any residue left on matting surfaces(pistons/bores include) use some scotch-brite to clean it up. the buna o-rings can be found at any hardware store or mcmaster-carr. if you have any more questions post em up. DEAR GOD DO NOT USE THE PIECE OF SILICONE HOSE!!!!!!!!!!!...aslo make sure if you are pulling more than one caliper apart that you keep the same componets in the same assy.

You're right, he's probably talking about a piston seal. I agree, rebuild it with the stock kit and it should be fine.

However, there are two halves to the caliper that should never be separated. I am thinking that if those two sections were separated, and there was an o-ring in between them, THAT would not be good. If that's the case you could have a hard time finding a matching replacement o-ring. It certainly won't be in a caliper rebuild kit.

Dave

NO I am refering to sepperating the halfes... there is usually just a buna o-ring sealing the crossover orifice(splLOL?) No it is not ushually in the rebuild kit but it can be found in any metric o-ring set...the piston seals are a square o-ring which I would suggest getting either through oem mazda or AP if you know the size. Its really no big deal seperating the halfes its just an o-ring groove....ther is no magic behind it.

it was two pieces to begin with, just replicate the original assembly process and you should be fine.

That's like saying you can't take and engine apart and put it back to gether again. doesn't make sense. Unless somehow magically the parts would never seal back together properly after separation and replacement of the proper sealing items?