I can only speak to a 126. Remove the panel by opening the roof ~ 8" and use a plastic lever inserted near the clip to pry down. The clip should pop out and the panel pulls forward and out.

Now the cable that moves the roof is exposed. There is a clip that holds the cable to the front of the roof. Remove this clip. Note that the hole in the end of the cable is larger on one side and the cable will need to be in the proper orientation during installation. Simply use pliers or a screw drive to get it aligned correctly.

Now that the cable end is disconnected, operate the sunroof switch to the rearward position so that the cable retracts. Move the sunroof back by hand. Simply give it a shove. There should be 5 counter sunk screws that hold the top of the rail to the car. Remove them all on both sides. The top of the rail should come off. Note the correct orientation and don't mix the sides up.

Move the sunroof forward. Sit in the car and somewhere near the middle of the track there should be a bolt with an 8mm head. There is one on each side. Remove the bolt from both sides.

The sunroof is now completely disconnected but it may not be apparent. You'll figure it out by looking at the FSM, YouTube university and the sunroof itself.

Do not remove the screws that look like the easiest way to get the sunroof out. It will be a beotch to get the thing readjusted.

You should clean the 4 drains 1 each in the corner. Harbor freight makes an inexpensive snake that fits. It will be a hassle finding the hole until you have understood where they are. The sunroof frame has a metal drain in each corner that connects to a rubber drain.

Clean the rails and lube them before reinstalling the roof. MB has special paste that Roy used to send out but SlyGlide seems to work good enough. You don't need much grease because it attracts dirt and gets gummed up BUT grease is necessary because a dry slide doesn't work either.

I now clean my rails once a year during the summer. It takes less than 30 minutes once you figure everything out.

You really need the FSM destructions even with the bad pics.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

Reviving this useful thread for a warning about procedure.

Make sure to remove the screw holding the plastic handle surround BEFORE you try to pop the headliner clips from the sunroof! Mine did not survive the mishap.