What you are referring to as a sprocket, the factory calls a pinion. Several years ago I found on Ebay a pair of replacement pinions and bought them, the only time I have seen them for sale. You are required to peen them onto the backing plate. Fortunately, I have not had to repair these on my 2 ton COE and cannot give you any advice based on experience. You could also try welding up the pinions where they are worn, or perhaps remove them and use a screwdriver through the hole to adjust the brakes, just like a smaller truck. Let us know how you solve this problem!
By the way, I believe that this type of adjustment was normally found on the 1 ton and larger trucks.
Good luck,
Kent
