I re-used same initial air gap spacer. Clutch turns very slowly when A/C on (not at all same speed as pulley) and very very slowly when off--but should not turn at all--should it? Not sure if air gap, bad coil, relay, or what.
Serpentine belt replaced year ago by dealer. A/C was working great till it just stopped a week ago and I noticed damaged clutch hub and a bit of clanging as it spun slowly. I took hub off. Pulley bearing grease cover was loosened by the failed hub and came off. No unusual other noises after hub removed--but am worried about bearing exposure to elements.
But not clear why clutch will not engage and fully dis-engage. Is gap too small? Should I be able to manually spin hub when A/C is off? Quite hard. I measured depth of bore in both hubs and they were within .004" of each other. I did not check coil resistance or anything else.