I think I read somewhere (and saw a photo) that leather is used on the backside of the bakelite as a gasket to seal it. Leather wouldn't surprise me, since it was also used in the overdrive solenoid.
-Kevin
Are you saying that leather was to ride on the distributor shaft?
From what I can can gather, the whole purpose of the entire assembly goes like this:
-spring/hard plug puts pressure on the side of the distributor shaft to prevent the points from wobbling as the shaft wears in its bore over time.
-the grease cup is there to hold tension on the spring/hard plug, and provide an easy way to see that there is lube where the hard plug rides on the shaft. I don't see where there would be a need for a seal at the hard plug area since the grease needs to be able to get to the hard plug.and distributor shaft.
There is a leather seal on the rim of the cap which keeps the grease from squishing out when you turn the cup cap in every 5-10 thousand miles.
