Passenger side caliper bracket will not close after brake pad replacement

This is the first time replacing my brake pads. All went well, parts fit accordingly. Also, I am a novice, with limited vocabulary in this area, so I'm going to try my best here, please be patient, but I am very competent, just learning.

The problem is with the front passenger brake caliper bracket. I can't get the clamshell to close all the way at the bottom so the bolt will go in. I have removed, cleaned and lubed the pin, so I don't think that's the problem. I cannot see any obstructions anywhere that would prevent it from closing. The pistons are pushed back all the way. I've taken a wire brush to the rust. It just won't finish closing. If I struggle, I can get it within 1/8 of an inch but the bolt just won't align!