Attached is a photo of one of the rear rotors on my '03 Explorer. All four rotors look similar, although the rust is a bit more scaly on the rear. All four corners need new pads, and based on the amount of rust on the rotors, I plan to replace them as well. What I'm looking for input on is the ring of rust around the outer edge of the pad contact surface on the face of the rotors. I realize a small lip of rust in that area is normal, but this seems to be a bit much, and definitely overlaps the pads in that area, so it seems there should be pad contact there by design. Is this caused by the caliper pins not functioning correctly? If so, it is likely that servicing the pins when I do the rest of the work will cause the calipers to function properly again? I'm trying to put together a Rock Auto order, and would like to order the calipers along with everything else if it is reasonably certain I will need them. If the pins need to be inspected to determine whether they can be brought back to life, I could order the pads and rotors from Rock Auto, then get calipers locally if they are found to be needed during disassembly. Any input is appreciated!