Bob , Their don't seem to be a method everyone agrees on. If it isnt to with in .00001 of a degree some will just constantly find fault with any method even though within 1 degree is acceptable from the factory. That said , I am not going there any more, tired of hearing it . I put an digital angle finder vertically on the heads of the bolts on the diff cover and logged that number so I had a number to reset the caster to if it changed because of swapping the Joints each time , which it did. On the bolts mine read 84.5 degrees if that helps.