The only thing holding it in is the right bearing from your picture. We often use prybars and tire irons around the outside rim of the plate in the picture to get it started. We use a engine hoist to lift up on it as we pull it out, Do not try to save the left bearing and housing. It is about impossible to save and it is best to cut it off and buy a new one. Make sure and check the rotor bearings and elephant ears on the rotor. The elephant ears should have a business card thickness of space or gap between them and the tube or housing. The elephant ears can be hard surfaced back to the original shape if you have a new one to pattern it off of. Once the leading edge gets rounded they do not grab the material as well. I would also install a knife on the dogs tongue at the entrance of the rotors.