For lower bearing, best find someone with a press. It need 3 to 6 ton to move. See process here:
https://flic.kr/p/2jhxS16
Or you can cut the bearing with a dremel. Be carefull to not damage the stem
Or you can weld some scrap metal to the beaging race and hammer it while hot.
Any method, take care of the threads on stem.
Outer races go out easily with a long chisel.