I think I can say that I have worked on a fair few Weinmann side-pulls, stripping and rebuilding them, but they're all earlier ones with a nut at the front and a "Weinmann" marked washer underneath.
What I am trying to work on now is another pair of black 500s, with quick-release lever at the housing side. Instead of a nut it has the black plastic knurled cylinder instead with a thin hexagonal pin in the middle. I cannnot figure out how to strip it down. Any advice?
