Thank you, EFT.
That bearing is stuck pretty well. I was able to get it as far down the shaft as it is simply by setting the shaft "head" end up on a piece of wood on a concrete floor and then tapping the "head" with a hammer (another piece of wood on the "head" so the hammer didn't mar it). However, it's now stuck. I tried sliding a piece of wood between the bearing and the head and tapping the wood; no luck. I tried heating the whole thing to 350F in my oven and then tapping; again, no luck. I tried a bearing puller from the auto parts store- jaws weren't long enough. So I'm a bit stymied.
I'm also having the same difficulty in reverse. The bearings are not sliding back into the worm wheels easily (I did have to tap them to get them out, too). Should they be a pres fit, or a slip fit? Would a little light sanding with some sandpaper or emory cloth be in order to make reinstalling the bearings easier? If they are supposed to be pressed in, I can borrow a suitable tool from the auto parts store I'm sure.
On a different topic: what about removing the shields from the radial bearings to remove the old grease and repack them? The mount, I hear from my club, is close to thirty years old and the bearings, while smooth, are pretty stiff. Some of the original grease I removed had turned into wax, so I will guess the same thing happened inside the bearings. What is the likelihood of removing the shields and reinstalling them without damaging them?