It's an old story, beemuker. To loosen seized parts, heat, penetrant, and knocking with a deadblow mallet or hammer often frees them. The wheel has a spacer behind it. Heat that area with a hair dryer or heat gun, soak it with liquid wrench, tap around the wheel with a mallet or hammer, drink a demitasse of cuban coffee, return and knock it a few times; it should release it. Repeat if necessary until you're so wired by coffee you need hospitalization. Keep control of the wheel while you knock it so it doesn't runaway when it releases and then damage something or someone.
