Need cylinder ring for brakes

Hi, I was wondering if anyone could tell me where to buy a cylinder ring for the rear calipr piston. I have tried Ford and the do not sell the kit anymore nor could locate one, Autozone had nothing for the rear discs in our cars and Car Quest didnt ave anything either. My caliper is in good shape other than the cylinder ring. Thanks for your help.

Ask Nitro_X where he got his parts http://www.turbotbird.com/techinfo/87-88...ebuild.htm