My rear abs rings broke when I took off my discs. If I got new rings, would it work by cutting in half so I didn't have to take out hubs and split to get then on

 

Mine are just badly corroded and need replaced, I had considered doing what you've suggested too and I don't see why it wouldn't work if you did it neatly and with a very fine blade. I opted to get rid of the ABS all together. Much better brakes in my opinion.