Bought replacement rear caliper, because of a stuck piston. The old caliper has a brace, or metal stop, bolted to it. It appears that would "connect" with a large metal piece attached to the body when the shocks are fully compressed. What is the purpose of this thing?

My problem is that the replacement caliper seems exactly like the old one, except there is no place to bolt on the metal brace. It was really cheap on ebay, I hate to send it back, but don't need a new problem either.

thanks for the help!

also, what is a good anti squeek for the brake shims? I have some red tacky spray stuff that does not seem to work.