Cam Seal Replacement
I just resealed the upper timing cover and replaced the cam seal on my '88 260E. I installed the seal in the cover first, but it was difficult lining up the cam seal and the timing cover on the studs and it is easy to damage the seal while installing the cover.
Mine turned out okay and the timing cover is as dry as a bone but if I had to do it again, I would install the seal after the cover is in place. Use a block of wood to drive it flush with the face of the timing cover. I also used some 600 grit sandpaper to smooth the end of the camshaft so it wouldn't cut the new seal (it was very sharp).