Albeit I'm new here, I am a bit lost on this thread. Is it about hub bearings or disc brakes? Front or Rear? 3600 or 3800 series? If it is for the rear I have found that the 3600 rear axle is a 14 bolt used up though the mid '70's and think these kits would work for the rear:
14 Bolt Disc Brakes Conversion
14 Bolt Disc Brakes Conversion #2


1950 3600 Advance Design
1996 Restoration with flat bed
Current in work: Disc Brakes, NV4500 5 Speed, Late model seats, Bed rebuild
Future: Fuel Injected/Turbocharged 235