This is where it can become slightly tricky. On this Mitsubishi built alternator the rear bearing is simply a light press fit into the rear case. To remove the rotor I just placed the shaft in the vice, being careful to only grab the shaft nut, and then lightly tapped the case with my lead hammer while rotating it so it came off evenly. I would not use a regular iron hammer to tap on aluminum but it's up to you. Remember this is a light tapping not pounding. Be very careful when tapping the case and removing the rotor as you do not want to damage anything. Many of these small case internal fan alternators are assembled in a similar fashion.