I'm looking to replace part of a "mixing valve" manufactured by Crane. The shower parts say they were patented in 1914. And the ones I have appear to be original to the house, which was built in 1915.

Any advice? As a non-spe******t, I'm finding the earch ****** has been a dizzing experience. I'd love to keep the hardware because it is beautiful. but I've got to get it working properly.