I would say it shouldn't be your brass bushings - unless there's major rust on the pins. Also, you must use the supplied guide pins that came with the brass bushings! (if you use stock pins it may cause the binding issues described.
Here's my suggestion:
(assuming fresh brake fluids and proper bleeding along with those re-manufactured calipers... )
If you're still experiencing random brake binding, I'd suspect the hub bearings has failed on that particular side.
Remove the brake caliper completely (leaving the rotor on the hub) and give it a spin, see if it is spinning smoothly without
'odd' noises. If you need reference to what a failed hub/bearing sounds like, search my vids on my channel below.
Let us know what you find out.
Last edited by BimmersGarage; 11-06-2012 at 12:29 PM.