Truth be told I've never done a 41 G506, but I've done a bunch of other types and sizes of wheel cylinders. I would disassemble the wheel cylinders. Remove from backing plate, use air pressure to blow out the pucks. I like to wrap them in a rag to prevent parts and old fluid form flying. Sometimes if I get nervous I blow em out in a gallon can. More aggressive means may be necessary. If the bores are in good shape and not pitted, I'd rebuild them. If not, replace them. I don't know the quality of the new ones. Thing is these are parts you are really going to depend on, so it's your call. Have fun............
