Bearing retainer: Some are just pigs! I keep a new one in my “spares” permanently. If you have one, they usually come out! As a LAST RESORT, you can take a really sharp chisel and drive them inside out, away from the threads in the hub. They are brittle and will crack in one spot. Then drive it in towards the centre (where the shaft goes) and it will “peel away” from the hub. Only hit the ring, don’t damage the threads!