48 and later 3/4, 1, and 1.5 ton have the same axle beam which is noticeably larger than a 1/2 ton. 1/2 ton spindles won't fit on the larger truck I-beams.
Some people swap whole 1/2 ton axles under the 3/4 or 1 ton but then you've got a 1/2 ton truck...
The idea of using 1 ton stuff and adapting large disc brakes is to have an axle suitable for holding up and stopping a working 1 ton truck.
Grigg
