First off I would like to thank you all for the information. I have checked the search history and I believe the Axle Nut size for my1950 B2B is 3/4 x 16 castle. I was driving this afternoon and for some reason the pass rear tire decided to try and escape. What I notice first was a thumping in the rear,then the brake peddle went to the FLOOR and the engine over revved. I walked around to the rear and was amazed that I saved it from doing more damage. Found the two halves of the split pin in the axle hole but no washer or nut. Had to jack it up to pull the tire, then had to pull one shoe to mount the tire/drum back on the axle.
I hope to get to the auto shop to get a proper washer and nut but the only way to get it to roll up the bed was to use my Vintage Plomb Pebble Finish Combo Wrench ( MFD USA 1945 - 48 ) found a 8d common nail in my spare parts. The tow truck driver was blown away. So I guess I need confirmation on the Axle Nut Size is the Castle Nut Size SAE 3/4" x 16 ? Thanks All for the great times I have enjoyed the posts, Rod