I was working on a 1990 240 today that had a leaking sunroof. the first thing I checked was that all 4 drains were working. The all seemed to be draining ok. from reading archives and looking at it myself the best I could tell is that the only place a water tight seal is needed is in the back. The front and sides do not seem to need this as they just drain into the drainage gulley and then out the drainage holes. The back part of the sunroof doesn't seem to be as tight as the front. The Volvo green manual mentions that the vertical height can be adjusted in the front and back. I pulled back the interior cover and could see how to adjust the front but not the back. wondering if anyone has adjusted the back verical height adjustment. also wondering if a height adjustment might fix the leak or is a new rear seal likely needed. also heard something about a TSB and butyl tape. is this a possible fix.