The belt shock pushes the tensioner all the way up against the pulley. You really cannot set the tension until you have the belt on.

On the TE, I looped the belt all the way round except for the AC compressor, then pulled the belt with one hand and pushed the tensioner pulley with the other until the belt would fit over the last pulley.

The tensioner nut just falls through the hole until you get the belt on.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

" As soon as I start to run the nut down on the adjusting rod (ccw), it pulls through the bracket. Once its through the bracket it just runs down the rod. No adjustment."

This may be part of the problem. You adjust tension into the belt by turning the nut CW. As Gilly said, the nut needs to come up through the bottom of the bracket so that the wide "brim" on the bottom of the nut is against the under side of the bracket. Imagine that the nut is captive under the bracket, and that when you turned it either way it wouldn't move up or down but rather would force the adj. rod to move up or down. Seeing as the rod and nut are LH thread, when you turn the nut CW, you're pushing the rod down, forcing the tensioner pulley to rotate CCW as viewed from the front. To install the tensioner, you need to run the nut CCW onto the adj. rod all the way down to where the end of the rod is flush with the top of the nut, if possible. Then, assemble the rod, nut and collar onto the back of the tensioner. With your left hand holding the tensioner body and your right hand holding the collar and rod onto the back, use your third hand to position the nut so that it slips up through the bracket from underneath. While using all three hands to hold these parts in place, you can then thread in the center bolt and run it in finger tight with your.....um, I mean your uh...., oh hell, just scream for help and when someone comes, tell them to screw in the bolt.

Now, wasn't that easy?

psfred,

On my car, the shock didn't push the tensioner either way. It did, however, damp movement rather heavily in both directions IIRC. I remember that I had to pull the tensioner over to get the belt on, and when I did it just stayed where I put it.

Gary

Now I realize after reading Garys 2 posts, that maybe the only problem is the nut is being turned the wrong way? The nut, when you turn it clockwise, is pushing the threaded rod DOWN, which tightens the tensioner.

I also agree about the shock absorber part, it makes it harder to move the tensioner, but doesn't exert any force in either direction.

Gilly

I had the exact same problem last weekend putting the front of my engine back together. It turns out that the tensioner adjusting rod will do this if it is on the back side of the swivel. So, in addition to being on the passenger side of the tensioner, the rod has to also be on the front side of the swivel joint to work.

BTW, the pictures here helped me out a lot. Thanks for posting them.

-anthony

The reading of all these posts tell me this fan belt tensioner adjustment is not for the average driver (half mechanic) to mess around with... You can't leave this to just anyone, I'd sleep better knowing an "A" mechanic dealer trained took care of this on my car.. The question is who and where you take the automobile to be fixed right, without some idiot making it worse..
I have adjusted many belts on Jags, MGB's, GTO's whatever... but this car has the German over engineered simple adjustment, made impossible for even a good smart Do it yourself person to get this done ! It's too hard...

All these posts make sense on paper, but way over my head...to try this myself for my W 126 300 SE ...so now where do I take it ?

Long Island, New York..

This is about as clearly as I've found the procedure spelled out - https://wiki.bentleypublishers.com/display/tech/Mercedes-Benz+E-Class+Owner's+Bible+(1986-1995),+Update with the caveat that some models have the image of a ramp rather than tick marks on the tension scale.

If that's not enough, here's a discussion site for NY shops - New York - PeachParts Mercedes ShopForum

Sixto
87 300D