<edited due to insufficient research and gross stupidity>
If you can whip them out (and it's a big if) without damaging them, you'll find the rust is from the brake pad backing plates and might clean off without too much problem. Your bigger problem will be getting them out though. Judging by the state of them, they'll be stuck well in there. I'd take the pads out and stick a block of wood between the pistons, then pump the brake until they're almost popping out. Then I use a brake piston remover (quite cheap on eBay). Whatever you do, don't use pliers on them. Brass is very soft and if you mark or dent the outer surface, they're scrap.
Get the callipers and pistons immaculately clean, especially the grooves the seals seat in, and use red rubber grease to rebuild them. The last set of OE seals I bought actually came with a little sachet and they're worth buying OE, I think.
If you can whip them out (and it's a big if) without damaging them, you'll find the rust is from the brake pad backing plates and might clean off without too much problem. Your bigger problem will be getting them out though. Judging by the state of them, they'll be stuck well in there. I'd take the pads out and stick a block of wood between the pistons, then pump the brake until they're almost popping out. Then I use a brake piston remover (quite cheap on eBay). Whatever you do, don't use pliers on them. Brass is very soft and if you mark or dent the outer surface, they're scrap.
Get the callipers and pistons immaculately clean, especially the grooves the seals seat in, and use red rubber grease to rebuild them. The last set of OE seals I bought actually came with a little sachet and they're worth buying OE, I think.
![[Image: 125377.png]](http://mefi.us/images/fuelly/smallsig-uk/125377.png)