@chapmanruss, your history lesson helps quite a bit. Thanks for taking the time to write that out. And @everettdavis, you were absolutely correct. I checked the vent cover and sure enough, it says "Mark 5" right above the serial number.
JPG, I did as you suggested and pushed the fan sheave back down to uncover the marks I'd inadvertently made when trying to keep the spring compressed long enough to remove the nut. I sanded uniformly around the shaft using 120, 220, 320 and 400 until all but the indentations were removed and then the fan sheave and spacer came right off. This had the added benefit of making that part of the shaft all nice and shiny. ;-)
@everettdavis, I've ordered a new 504205 Spacer Sheave from ShopSmith. They don't seem to differentiate between motors in the exploded diagram and mine is different, since I don't have a washer and retaining ring holding the spring on, but hopefully, they are the same size.
As you can see from this picture, my centrifugal switch, as well as the spinning brass part beneath it are quite different from the pictures in the AO Smith 1 1/8 HP thread. On my motor, the connecting wires are soldered on, so I'm going to have to remove that to get to the back bearing. Since I hope to switch out all the old brittle wires anyway, is there a replacement part that I should consider here with detachable wires to make any future work easier???
The spinning piece has a single spring, vs. the two springs in the later motor, but it came off the same way revealing the flat head screw. So that part came off without any issue at all.
Now back to the front, the cover now comes off and the bearing is held in the cover by a small plate. The plate came off by removing the two small screws to reveal the bearing.
But there is no obvious way to use a traditional tool to remove this bearing. All I could find was a small space where I could push the bearing out with a flat head screwdriver. Not ideal perhaps, but it worked.
Unfortunately, it damaged the bearing, but not to the point that I couldn't read what it said.
@everettdavis, here are the particulars that I've collected so far using my calipers. Am I missing anything?
- Text on both sides of the bearing: HOOVER 77203 MADE IN U.S.A.
- Diameter D = 40.01mm
- Bore d = 16.87mm (0.663") (Not sure what to make of the non-standard size.
- Width W = 11.98mm
- Shaft = 5/8" (0.626"/15.91mm)
So then. I need a bearing where D is 40 mm and W is 12 mm. But what should "d" be? Would I select 16 mm, as it is slightly above the shaft size, but less than the current (very worn) bushing, or should I ask for a "d" of 5/8"?
Thanks, guys! I'm making progress one baby step at a time. I couldn't have made it this far without your help.