everytime i have done rear brakes this has happened to me.
ONly placy that carried parts for the brakes was Maverick auto parts. there is one on fullerton and one on central and cicero!
What sucks is you will need to get a loaded rear caliper. because the parts by them selves are hard to find. ALso they will give you a core return on your brake.
773-278-7111
rear right part # is 16-4645
99.00 for the loaded caliper plus a 50.oo core !