I removed the small brass plug, removed the felt pad, put a few drops of Kroil in there, worked the speedometer cable back and forth, and it freed up.
From there, I hooked the end of the speedometer cable to a drill, put WD40 in there, spun it around some, until a lot of gunk came out.
I then put the straw of a gun scrubber bottle in the hole, and sprayed as I turned drill until it seemed clean.
After that I let it dry, put a couple drops of gun lube on bearing, soaked felt pad put it back in place, and replaced brass plug.
I reinstalled speedometer and it's totally accurate, matches up just right with phone app GPS.
I'm pretty surprised it started working, it was completely seized up and had been for years.
Last edited by BurningTracks; 07/22/2022 9:55 PM.