How 2 loosen alternator bolts ?????? - PeachParts Mercedes-Benz Forum

tomm9298 · #1 09-23-2004, 02:36 PM

I am attempting to replace all of my drive belts. The alternator adjusting bolt ( by the drive belt pulley - upper). I can't seem to get to it to loosen it. This is not the bolt on the left upper when facing the car from the front, but the bolt on the right side of the alternator. This is a 17mm bolt. I canot use a wrench, too much offset to avoid existing belts. I tried a ratchet with a 17mm socket and 3 inch extension. Fan is too close to properly align. Will a 17mm deep well socket work, or do I have to remove the fan, clutch, and pulley?????

1984 300d turbo diesel sedan.

leathermang · #2 09-23-2004, 02:38 PM

I don't know how to describe it myself.. but I do remember this being posted already.... might be faster than waiting for someone who does know.

R Leo · #3 09-23-2004, 02:56 PM

Disconnect the battery first, then the wiring to the alternator.

Next, come in from above and go behind the alternator with either a very shallow 17mm socket or a 12pt 17mm box end, and take the entire adjusment bracket loose from the block by removing the fore and aft bolt in the bracket that is closest to the block...you'll have to loosen the other two bolts (the pinch bolt with the adjuster and the bolt on the bottom. Leave the adjuster bracket and weird adjuster bolt on the alternator.

Then, go under the car and remove the bottom fore and aft bolt. The entire assembly will now come out of the bottom of the car.

Reinstall by putting the adjuster assembly (bracket, spacer, and weird adjuster bolt/nut) together on the new alternator while it is out on the bench. Leave the adjuster pinch bolt loose and come in from the bottom with the alternator, reversing the above steps. If you leave the adjuster pinch bolt loose, you can easily jockey everthing around and get the remainder of the bolts in place. If not, you'll struggle for an hour and get nowhere. Don't ask how I know this.

Good luck.

tomm9298 · #4 09-23-2004, 02:59 PM

I do not want to remove the alternator, just loosen it enough to change the belts. Can I still use your procedure??

R Leo · #5 09-23-2004, 03:09 PM

Sure, just don't remove the alternator. All the bolts still need to be loosened in order to move the alternator freely.

The adjustment is weird, nothing like American iron. When you get everything loose, put a socket (13mm I think) and ratchet on the long nut that is positioned crossways. Turning the nut CCW pushes that pinch bolt back towards the engine block and consequently, moves the alternator inward so you can remove the belts.

Neither of my 123s have enough throw to get the inner belts off very easily. I've always had to work them off by moving them first to the outer sheave and then off the car.