Before you have too much time invested in those caliper brackets, run a tap through the caliper pin threads and make sure they are good. In your pics they look a bit rusty. They can be nearly impossible to heli coil as there isn't a lot of meat there to hold a sufficient number of heli coil threads to do the job. Been there, done that...had them pulling out/unthreading on me when screwing in the pins even after trying to loc tite the heli coil in place...that's one advantage the sliders have over the pin type brackets...