Brake wheel cylinder

From Dave Snow: Had information from John P that 54 plymouth wheel cylinders are the same (or will work) on our Royale's. Having researched this I did not find that they are the same although I am researching this further. My question for the group is what has been your experience with replacement or repair of the wheel cylinders. Do you have any sources for repair parts or new matching cylinders. The information from Al about the duesy parts being the same is great and I will follow up to order those once I pull the master cylinder and measure the bore size. Thought I might see if that same supplier has wheel cylinders that match on the notion that maybe the Duesy's are the same as the Royale's. Any Thoughts?