I used axle that was already set up with disc brakes. It came out of a late model HD3500 dually. The spring pads were about 3/8" different from the original so I just widened the alignment hole about 3/16" on either side. The pad was also set up for a wider leaf so the U bolts wouldn't quite fit. Just due to the corners of the pads basically. So I cutoff to the corners of the pads and it works fine. I had a local hose shop custom make a hose that connected the original brake line to the new axle. The new flex line was made longer to accommodate the different mounting location. I did not need to do any mods for the shocks, as those are integrated with the U bolts and frame mounted. Now with the disc brakes and a taller set of gears, going from 6.17s to 4.63s, I'll have a better ride and easier cruise.
And offtopic, I'm putting in a TH400 from and RV and I just acquired, for $50 (yes Fifty), a scrap Stepvan with the disc brakes in the front that has the 5-10 lug pattern and 19.5 wheels. I'll use the front spindles and brake hardware to convert the front brakes to disc as well just like Grigg's Tech Tip. Which is brilliant by the way. The local spring shop will custom make a set of bushings to match the kingpins off the bus and the spindles off the Stepvan. Then just hook up a brake line or two and that's done too.
