I have removed the sunroof frame/panel from my W126 for refurbishment. I'll be doing this on both of my 116s shortly as well, and they may even be identical.
Between the sunroof frame and the roof of the car is a foam seal. They are not very expensive from the dealer, but I'm wondering is there an alternative to this? It may be that when this foam starts decaying, it promotes rust.
I also found that the rubber seal across the sliding roof panel at the rear is critical. When in good...