To pull instrument cluster, do a search on ebay for mercedes instrument cluster tool (or hook). They should not cost more than 10 bucks or so.

You insert the two hooks at either side of the instrument cluster, at the lower corners. Slide them in between the cluster and the dash material. Turn the hooks so they catch the back side of the cluster. Make sure your steering wheel is all the way down and all the way out. Now grab the two hooks and gently but firmly pull toward you. The first time you do this, you will be freaked out because of all the force you need to exert, but it will sort of slide out with enough force, To put it back, simply line it up0 and push it back in.

There's not a lot of extra wire and I believe you have a speedometer cable to detach. But a flashlight and patience, and you will separate the cluster from the car.

As for the sunroof, if you hear gears clicking, you may have a bad gearset. Or you may need to clean and relubricate your sunroof tracks. You should use Benz sunroof grease. As for actually doing it, you probably should go on ebay ro MBUSA and buy the entire service manual on a cd or dvd. Ebay is about 20 bucks, MBUSA OEM version maybe 100 USD.

Good Luck!

 

Hey thanks so much for your interest,time and advice.
I'll do as you say and it'll happen. These cars are so well made.
I've got very rusty '79 116 and a not so rusty '80 116 and i can practice on
the '79. The sunroof gearbox in the trunk has the gear cluster so i'll compare the two. The '80's roof closes much easier than the '79's but not all the way.
Will keep you posted. Have the power steering pump filter on order. Noise is
less, thanks ulysees (-: