Yeah mine is 2WD so it looks a little different, but it's definitely the 15mm bracket bolt. One was tight, but I was able to get it off with some effort. The other won't budge at all. Thought about using a long piece of pipe but pipe isn't something we have a lot of around here.

: I was going to get a long breaker bar at Advance Auto today, but found they don't have any. Never does one parts store ever have everything I need.
Wasn't planning to take the caliper off of the bracket as to avoid dealing with the brake stuff, but it could end up being my only option. Not going to give up without a fight first tho, altho I feel like I've been beaten to hell already...
flex head could be useful... I was having trouble keeping it dead on because of the way the bolt is in there. I'll check that out.
BTW, don't forget to get cotter pins beforehand, especially if you've got parts you need to unbolt but not replace. You're supposed to use a new pin each time.