Nice brat! Um you do know the caliper pistons screw in right? They don't slide in and out like a regular caliper since the park brake is up front. Learned that the hard way myself.
I tried screwing it in for 20 minutes with no luck so i took off then i hit it twice with sledge and put it back together. Once it was bled i tested it out to make sure it was working right which it was. I test brakes on gravel so i can tell what brakes are grabbing from the skid trails from hard stops.