I have an 89 GMC van that I need to get running before I leave on my annual wheeling trip. (No I don't wheel the van!) Anyway the air conditioner compressor is locked up and evidently the bearings are out of the clutch. I have the puller for the clutch but I can't get a socket on the nut on the shaft. It seems a thinwall 9/16" socket will almost go on, so my thought is maybe it is 15mm, but the only 15 mm sockets I have are too thick walled to fit. Before I grind a socket down can someone tell me if that is what I need. I checked at the two parts stores that were open today, but they were as clueless as I was.