I hope you guys can help with this one. I went to the MB dealership and purchased a new ignition for my '86' 420SEL. When I first purchased the car, there were 2 different keys for the car. One key opened the doors and the trunk, the other one was very thin and fit the ignition. The plastic piece that encases the key was worn and split. The previous owner for some reason, had the tumbler changed and had a different ignition/key. I like the idea of only having one key for everything. My question is, to make a long story short, how difficult will it be to change the tumbler? Can it be done by a do-it-yourselfer? How do you take the ignition out?