hopefully it was just a type above but Your 6400 is a 2 ton, not a 1 ton and no, the master cylinder is not the same as a 1/2 ton pickup. Napa and Rock Auto should both have rebuild kits for the front wheel cylinders and the master cylinder. I am not sure about the whole cylinder. Browse or search the big bolt forum though, there was a thread on this exact topic that came within the last week or so. Also, do you have a 55.1 or 55.2 (AD or Taskforce truck). They made a model change mid-year in 55.
