I just replaced the rear seal in my '76 240d and it wasn't all that hard. The worst part was the defroster. I couldn't find wear the connections for the wires were so I cut the wires and made my own connections. The seal in my car was just like an old VW so all you need is two people (one to lean on the window) and some clothes line. Insert the clothes line into the inside groove of the seal and overlap the two ends at the bottom by about 3 inches. Position the window, have your freind lean on it and start to pull on the clothes line. Have your freind put pressure in the area were you are pulling and the seal should be pulled over the metal ridge of the window opening. The corners are a little tricky and you might want to make sure that your headliner in not loose. Make sure to put the trim into the seal while the window is out of the car. One thing I would do different the next time is to put a mark on the window and body to help with the alignment.

John Boyer