I have this old tractor 1963-1964. It was built using military components. The front and rear axle are both steerable. The axle has a 14 inch. dia hub with 12 studs for the rim. The tires are 18.00 x 26--newer tires would be 23.1 x 26. This might be called a 5 ton---not sure.. The model for the axle is a Rockwell PS 251 HX 12 I am trying to find a pic of the insides of this axle to see where the seals are located. Thinking if I could find what trucks or equipment these axles were on in the 50-60 70's it might be of some help. My pics are too big to put on this forum.....
I think your best bet might be to go over the http://www.steelsoldiers.com/ Lots of knowledgeable guys over there.