Brake cylinder part number

[Kaegi]

Roberts motor parts lists the 1 3/8 and the 1 1/4 pistons for 8 bucks each. The look like cast iron in the pic burt I would call and make sure if you want to buy them. I am going to make some soon just to hone my machining skills on a lathe and a mill my buddy and i fixed up for another project. I am not a machinsit so thought that might be a good part to practice with.