so I was changing my rear brakes today, and I got everything tore apart, and began putting in the new brakes. I twisted the piston down, but I cant seem to get the caliper back on.. the two studs that the bolts screw into to hold the caliper in place dont want to cooperate. The top stud moves in and out which makes it easy to get the upper part of the caliper on, but the lower stud has no give and I cant get the bottom part of the caliper over the new brakes. I have beat it with a hammer, tried prying it in with a C-clamp, I ever grinded down my new brakes to makes room for the caliper to fit over them. Idk what to do, PLEASE help!!