I need help tightening my belts- '85 300DT
 

Anybody got a diagram or picture or DIY article on tightening my drive belts. My alternator belt is loose and it's not charging my battery properly.
I've replaced belts before, but this is my first exploration under the hood of my Benz.
I'm sure I loosen certain bolts, then tighten, etc..
But a diagram would be helpful just in case it's not as straight forward as I hope.
Help a rookie if you can.
Thanks.
Jay

The alt. has three, I think, bolts you need to loosen. The last time I did this I bent a ratchet loosening the bolt you access "through" the fan.

if the alt belts are loose, they need to be replaced I bet. but to tighten any of the belts on this MB the accessory will have 3 bolts on the back side, and an adjuster bolt as well. the PS pump has nuts on the front that need to be held from turning.
it's pretty easy if you know what to expect, you will see it.

Yes, isn't one of them an eccentric bolt the will tension or loosen the belts when turned? I seem to remember doing that a while ago.

Not an eccentric, the really long 13mm head thing, is the adjustment bolt, but you need everything else loosened first. It's an "L" bolt, part of the upper bolt sticking out of the rear.

Now that I've looked....
 

It's the alternator belt that needs tightening. Although there are two belts going around the alternator pulley-it's loose too.
It does have what looks to be a tightening "mechanism" that looks like it will tighten up the alternator once I have the other nuts loose.
3 bolts? I only see two- and of course I don't have wrenches, just sockets-good luck getting a socket head on those bolts!
On my way to borrow a buddie's wrenches....

One bolt is accessed from below, that's the pivot bolt, I think, it is threaded into the alt. Another is that bolt I bent my wrench on, it has nut on the end, I put an open end on the back, the fan has a clutch on it, just move till, you can get a ratchet lined up. The third is the adjustment "L" bolt, loosen on back, adjust with the other end, long 13mm.

Finished! Man was that easy.
 

So once I pulled my gloves off, the sockets worked fine. But I'm glad I had my Dad's old rachets. There's not enough room for a rachet bigger than the diameter of the socket. And I needed a shorty for the bolt in the back.
2 17mm bolts to loosen- one in the back, one in the front. Then the 13mm "tightening bolt/adjustment bolt".
Now my battery can get a good charge on.
Thanks for the help and support.

That's why we're here.
Glad things worked out.

I am in the middle of replacing a water pump. The pump was the EASY part. Adjusting the (*@&#(*#@(*&^@# belts is a PITA!

How the hell did you get a ratchet in there? I have tried both bolts and cant get a grip. The "front" bolt head is blocked by the adjuster bolt.

Guess I am off to obtain a 17mm wrench. :mad:

After fighting the altenator on my son's Euro car,(1985) I found that two open end wrenches worked best. Once the upper and lower bolts are loosened, you can access the "tube nut" and run it down towards the altenator. This action causes the altenator to tighten as the tube nut runs on a bit of threaded rod, which is welded to the front side of the upper nut. You should have no more than 1/2" deflection in the longest side of the belt when tightened.