I replaced mine 4 years ago. Misshapen and broken bearings galore!
I just attached a masthead halliard to the bow roller and cranked it fairly tight. I put tape on the forestay thread to mark exactly how far it was tightened, then undid it. Removed the motor and furler gearbox from the foil and dropped the drum off.
There is a plastic plug inside the drum. When you prize it off all the balls just drop out. Once the top and bottom set are out the two parts just separate. Beautifully simple.
You may need a new plug. The inside is curved to match the curve of the inner ball race. This plug needs a ridge on the outside that fits the foil groove to stop it rotating and blocking the movement of the bearings. The ridge had worn away on mine so I had a new one machined.
Not a difficult job.
Ian. Ocean Hobo SN96