I've been looking into doing the exact same thing for the roof of my 240.
Anyone still able to offer any help/advice with this?
Cheers!
1. However long you think it will take, double it
2. Buy more than 1 spot weld drill there are over 100 to drill out
3. The front return on the windscreen pillars is a little tricky as the metal fold is complex
4. Be extra careful on the rain gutter spot welds, there's not much meat there
5. Learn to puddle weld if you don't have access to a spot welder.
6. The leaded joint at the back can be a little tricky to clear out and "un lead" a blow torch, wire brush and plenty of patience is needed, some of it can be skinny disc'd out
7. Don't try and take the roof off/put new one on by yourself, its fragile and tricky
8. Don't despair, with the roof off you will think "Oh what have I done" persevere and take your time, the devil is in the detail
9. With the roof off, treat the exposed metal to some protective coating, its been there a while and once the roof is back on, it will be there a while longer.
Finally Buy beer to celebrate, as once done (properly) its one of the most satisfying jobs you will do.........especially if it rids you of the dreaded sunroof.
Just some thoughts