headlight bulb replacement

I am trying to put a new headlight bulb in a 1977 SL 500. I took the protective casing off of the back assembly, the plug-in to the bulb, and the locking wheel. But now I cannot extract the bulb. I am sure it is easy with the right technique. Please help! Lowell

I solved the problem of headlight bulb removal. I jiggled the bulb and pulled back hard and the bulb came out. This was the original bulb so after 9+ years some small corrosion could have frozen the bulb in place. But I now have a new problem so I will start a new thread for it. Lowell