For the lines I once thought stainless was the answer, and did a truck in stainless. After that I found out about copper nickel lines and have used a bunch of that, I even imported and resold it for a while. These days it is easily available at most all auto parts stores. For example CNC-425 should be a good part number for a 25' roll of 1/4" line from Autozone, Advance and others.
Copper nickel is easy to bend, flare, and work with in general. Stainless on the other hand is difficult to bend, really hard to flare and requires the very best tools for good results.
Both are about as corrosion resistant, so the CuNi being easier to work with gives it the big advantage.
Assuming you've actually used (and I'm, sure fought with) stainless before I'd say if you try some copper nickel line you'll never go back to stainless.
About the rest of the brakes,
Is the goal to keep everything original?
If so then sleeving the master cylinder with Stainless is a good plan, or just purchase a new MC if available. I recommend against having it brass sleeved, if you do anything make sure it is stainless.
Here's some info on a source. I haven't heard of or seen his work lately but if he's still doing it that's where I'd go.
https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=477589&page=allAgain, if original brakes you just have to rebuild what you have, scrounge parts as you can, not so much is offered as a kit for rebuilding them like things are for the 1/2 ton trucks.
If you're looking to upgrade brakes an easy swap would be a whole 14 bolt rear axle, and you can get one with faster gears while you're at it if you like.
There is not a ready made front disc brake solution for the 1 tons. Some folks have used different parts form here and there and fabricated and machined stuff to work, but no kits. I put together some info here that may be of use for your dually, and of some use to single wheel trucks although perhaps not as much.
https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=725027#Post725027Third post explains how to make a 72.5" wide dual wheel 8 lug disc brake front axle. I still don't have the original axle width measurement for an AD dual wheel 1 ton to know if this is any help?
Grigg
