I have used the single pin caliper for years and have always had trouble with the caliper ----ing sideways and this wears the pads uneven. I have tried new pin bushings, etc. The brackets may be the problem where the pads rest on them, but not much to do here except buy new ones.
I can find some dual pin calipers from the late 80's which have a bracket that goes around the rotor. You have to remove the bracket to get the rotor off. Not a big problem, if the dual pin caliper is better. Any bad news about these dual pin calipers????
I know the early 90's calipers are dual pin but the bracket bolts are farther apart and wont fit on the 80's spindle.
Thanks
ANdy