From what I've read in this post, the main problem seemed to be after 40,000 miles the shaft bearing and face bearing on the shaft that the cable connects to wore out and allowed the upper rotating part(s) to cause the destruction.
Now that you've tore your speedometer apart, do you see any reason I couldn't remove the speedometer and apply some very light weight oil to the input shaft to lube the bearings?
There a few things to keep in mind.
1. Chrome ring un-crimping and re-crimping on the speedo case is going to show some nicks and cuts on its edges. They may be small or big cuts. This may affect the sealing.
2. The
bottom end (tip) of spindle for the speedo cup sits inside a very small pot-hole in the shaft for magnetic bowl
(pictures 2920C and 2907A). It cannot be lubricated from the bottom, where the speedo cable enters into speedometer. It is a blind hole for the tip of spindle to rest on.
This pot-hole is not accessible from the top in an intact unit, since it is completely surrounded by the round lip of upside-down speedo cup, which itself is enclosed inside the magnetic bowl. It is like a pearl inside a clam shell - can't reach it unless opened.
Cannot open it unless the RIGID frame around it is broken.
3. The
top end of spindle for the speedo cup can be accessed for lubing IF the dial needle is successfully pulled off the spindle
(picture 2916C)In my case, the two were glued. The broken end of spindle remained inside the dial needle.
4. There can be other reasons for malfunctioning of the speedometer - not necessarily the free rotation of spindles. One of them has been mentioned by GHG that the bottom threaded housing, for the shaft into which speedo cable is inserted, is also riveted to the frame. This rivet can become loose and whole bottom half of drive mechanism can start wobbling.
It MAY be possible to solder at that joint from the outside.
5. One can try and see how far one gets in fixing the speedo. But there is a good chance that it will need a new replacement.