I just did mine two months ago. I used a Dremel tool with the small cut-off abrasive wheel.
Be careful how deep you go, just about 3/4 way thru the ring. If you don't keep the cut-off wheel exactly lined up with the cut slot, it will shatter - you MUST wear safety goggles, eyeglasses are not good enough. I broke three wheels.

Then use a cold chisel on the cut, with the ring backed up on something that does not bounce. I used a brick resting on the driveway pavement. One good hit with 3 lb hammer and the ring snapped. It will slide right off the axle.

Same thing for the bearing inner race. it is a press fit too.

To assemble the bearing I hammered it into place without problem. The ring I couldn't get started, so the axle went outside (-10 C) and the ring went into 350 F oven for 1/2 hour. No problem.

Good luck.

'89 240 400,000 km.