After unplugging the cable and pin head, it is really difficult to get the clamp ring out holding the lamp. I tought I had to rotate it, it didn't move. I forced that using a plier but that was not something like corrosion or friction. Something was really holding it. I didn't go further since I didn't wanna break it. Does anybody have an idea to take it off ? Thanks.

 

I have a 300D from that same year. If it is the same round headlight that I have it takes a little jockeying to get out. Basically you just have to kind of play with it a while and use a little force but not enough to do any damage. That should get it out. You could always put a little WD 40 on the ring to make the glass slide through easier. Hope this helps if not let me know.

 

Thanks, WD40 really worked. What i did was very funny: I sprayed the WD and waited for a while. Then, I started tapping all around the ring using a screwdriver and a hammer. Just a little by little all around it made the WD absorbed fully. Kinda vibration thing helped too, I didn't need to use the plier again it just released itself as soon as i grabbed and started rotating it. Well, 20 years of bonding made me really think that it couldn't be opened by rotating that was so concrete. Thanks again.