I've been setting my brakes up, as they have ended up rubbing more than I'd like.
It turns out that through either a process of fretting or very tight bolts, the area where the bolt head seats against the caliper has become slightly concave. This results in a tendency for the caliper to move to the same position every time you tighten the bolts.
Now, obviously, the solution is to either remove the excess material around the concave area, or to rebuild that area to make everything level again.
As you can see, there's stuff in the way of just filing everything flat:
(shamelessly stolen image)
Any ideas? You can get in there with sandpaper and a finger, but it'd be a hell of a long job...
