Been there, seen it, done it, now dont take this the wrong way but your brakes are your life ! and others!
I can tell you by experience that in the end there not worth the hassle of mucking about with .
I've just spent the money on a new set up front and see what a differance they do make
John I will have to disagree with you on the worn wheel bearings being the most likly cause , yes this would cause this prob, but past history of these calipers must first point to partial piston seizure.
roland
now stopping in style 
