I just went through this with my '59 Viking 40 (1 1/2 ton). I wanted just the wheel cylinder kits, and bought two sets that wouldn't work. The first set came from a well known antique parts supplier, and the other set came from NAPA. It turned out that, both sets were for the original wheel cylinders that came with the truck from the factory. The problem is that the originals had long ago been replaced with after market ones. Although they (the after market cylinders) might work the same, the inside parts were vastly different.
I finally found the parts I needed by calling a shop that specializes in relining shoes, and clutch discs. This guy new exactly what I needed, and had the right parts for me the next day. He was even less expensive than the other suppliers.
The worse part, is I wasted several nice weather weekends with the wrong parts.
You will probably want to look for someone in your area, but I found the correct parts at "Auto Brake & Clutch" in Omaha, NE.
Good Luck
John
