Take note of the centrifugal advance weights and springs before removal. This is something you don't have to do either because the shaft assembly will come out intact. We're disassembling the mechanical advance because we want you to see how it works. It's a good idea to disassemble this mechanism for clean up and lubrication with high-temperature grease. The C4AF distributor has a different mechanical advance design than C5AF-and-newer distributors, which have smaller weights and a different type of rotor cam, just to name one difference.