I am having a bear of a time to get a rotor to come off a 93 s40sx vert. I have sprayed it with PB Blaster at least 10 times, letting it sit over 8 hours. It just will not break loose! I notice there are 2 threaded holes that looks like I could thread a bolt into that would hit the hub behind the rotor forcing it off. Would anybody know what size/thread this hole would be?