Sorry Ed,I'm not well versed on the mysterys of the inner workings of speedometers.
It might be something as simple as stuck/gummed up.
The light grease they were lubed with may have turned to gloop over the decades.
Especially as the truck was dormant for 25 years.
I know when I tore into mine the grease was like wax.

One of our Stovebolt stalwarts Denny Graham seems to know his way round these things,it might be worth sending him a PM.
If not,i'm sure he'll know someone who does.

Last edited by jockbolter50; 09/05/2011 8:36 AM.

1950 Chevy Advance Design 3100 in Scotland
In the Stovebolt Gallery
More pix on Flickr.
I've definately got this truck thing in my blood ... my DNA sequence has torque settings
"Of all the small nations of this earth,perhaps only the ancient Greeks surpass the Scots in their contribution to mankind" Winston Churchill.