Oversize 1.312" seals must be used with the seal saver ring. The added benefit of this seal saver is it presses back up against the rotor and then it has to be machined in a lathe flush with the end of the rotor giving the rotor shaft more material against the bearing which is helpful as most bearings have a large radius which can cause the rotor to pull in to the bearing harming rotor to end plate clearance.
Shaft collars are sold each.