6.9

Good timing, I am at the tail end of tackling this exact issue. Ironically, lube is most likely your last remedy with your described issues. The system consist of a motor in the trunk, a cable that has splines at the motor end and a rod at the sunroof end. The problem exists in the switch....much like the windows, it does not have a shut-off trigger and the motor continues until you release the switch. This puts undo pressure on the system and stuff gets bent over time. It also throws the clutch in the motor out of whack.

So, the first remedy is the rod in the guiding tube.... this is most likely your problem. You do not have to take everything apart ( as I did ) to solve this problem. There are playbooks on this site as well as the W116 site. It is fairly easy to fix. Basically, take off inside sunroof cover ( held on by clips ) by inserting a flat tip screw driver in between the 2 and pull down. The panel comes off and exposes the cable and tube. Detach the cable and operate system to close. This will eject the cable. The rod at the sunroof end is most likely bent. Throw it in a vice with rags and bend it back to straight. Lube the cable and reverse steps...and yes the motor easily accepts the splined end. 

The next issue could be the clutch is slipping in the motor. You can tell by the sound. If the roof is fully open or closed and you can hear the motor continue.....there it is! Let know if you get to this point.

Here's an interesting issue, folks...

The sunroof on my 6.9 opens just fine, and, most of the time, closes just fine as well. Occasionally, however, when I close it, it runs very, very slowly, as if it needs to be lubricated. I've lubed everything I can think of, but still the problem persists. It's only on closing, never on opening. If I "help" it along with my hand, it moves faster, but for some reason, closing seems to be a problem at times.

Any ideas?

Thanks,
Jim

1979 450SEL 6.9 (Black/Safran)
1987 560SL (Red/Palomino)

Driven with "old man" sheepskin covers!