Are you trying to pull them straight out. If they are similar design to the w126 they kinda roll out. You grab the part that is protruding and pull out while rolling the inside lip away from the center of the door. I'm taking all four off my car to get to the plastic strip around the windows.

Imo, it's easier to clean, prep and paint those strips if they are out of the car. The rubber seal is cooperating nicely though the metal plate's fasteners on the hinge side of the door are a beast to remove. I ended up cutting the heads off them to keep from bending the metal plate. I understand from my reading here that those nylon pins for the metal strip can be purchased at Tractor supply, fyi.

If this has nothing to do with the 123 bodies please excuse my wordiness and intrusion on this post.

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84 300SD
85 380SE
83 528e
95 318ic