You need the later caliper not the earlier 80-82 as they are different.
I am quite aware of this yes.. :shock2: The caliper is frozen, trust me - I am changing the brake pads and bent a cheap C-clamp trying to compress the pistons..I'm not on here trying to teach my grandmother to suck eggs but..... You do know that the front brake on the '83 only operates one of the front rotors?? So if this is news to you then try and operate it using the back brake.