Well, the bearing is out! Here is the next part of the story. The latest photos have been posted at Flickr:
Joujou Dufour 32's photosets on Flickr
After the last update, we undertook an effort to rotate the bearing 90º horizontally by continually moving the hammering point around counterclockwise 195º from the previous point. We were trying to expose more uncleaned bearing surface that could be cleaned. It did not work; we think the flanges were large enough to thwart us.
Penetrating oil was of very minor help.
Water ice was ineffective in shrinking the bearing. Only dry ice will do.
So, a decision point was reached: try dry ice again, or, knowing that I could obtain a replacement bearing, proceed with brute force to get the bearing out. I had handy a set of iron chisels, and a Dremel tool with attachments for cutting the bearing.
We started with the chisels. The 3/4" chisel imbedded itself into the flat edge of the bearing easily. At first the bearing was hard to budge, but then it turned more easily as the restraining material's surface diminished. We got near to the 90˚vertical rotation we were seeking. Next we used the chisels as bars to pry out more of the bearing until we could reach in to yank it out by hand.
Peering inside the housing, there was a substantial amount of light-colored, fine, granular powder. Apparently, this is the calcified algae that caused the lock up. The photos show it well. Also, it looks like the white distilled vinegar we used earlier never penetrated between the bearing and the housing.
(1) Clean, buff, and polish the aluminum housing.
(2) Clean the bearing, file down the chisel indentation; keep the bearing as a back-up.
(3) Install a replacement bearing—one is on order.
(4) Give Dufour an earful about this problem.