The bearing that fell apart is pressed into the "slave" roller. There is no way to get behind it. The roller is solid. The "master" roller has it's bearing in the body. These should be easy to remove. None of the bearings turn. They act more like bushings. I can get the 4 bushings for about $12. Maybe I will try to fix it. I ended up removing the one bearing with a grinder attachment on my Dremel.
I think I'm late to the game, but you need a blind bearing puller for this. Replaced bearing in my cereal killer a couple years ago after using my compressor to clean. Now I use vacuum.