All ears on this converstaion-I have had repeated issues will oil leaks from these seals. I thought the Nissan one had the steel pins enbedded within the rubber(one piece unit).
I also thought the aftermarket ones the pin was wrapped with the rubber, but was two different pieces.
Either way, I got it wrong , because mine leaks
check out this
http://www.classiczcars.com/forums/thread37250.html