Noisy Belts - PeachParts Mercedes-Benz Forum

420benz · #1 11-22-2006, 07:23 PM

Replaced all belts about 6mos. ago, and i can't seem to get rid of the noise of squeaking belts.I tried Belt Dressing,but to no avail.Any Ideas?

Dubyagee · #2 11-22-2006, 07:34 PM

I shut mine up with a squirt of black magic tire dressing.

420benz · #3 11-22-2006, 07:45 PM

Thanks i will give it a try.

Gary Ganaway · #4 11-23-2006, 12:32 PM

I had new belts put on my 380SE( 5 belts total) The one that occasionally makes a banshee squealing is the A/C compressor belt.I have to loosen the pulley and increase tension to stop the squealling. Have had to do this a couple of times since evidently I just can't put enough tension and tighten singlehandedly, so will solicit wife's help next time or might hae to get new pulley.

kiwi_bloke · #5 11-23-2006, 04:57 PM

I had this after replacing the belt on a 300E. Except we discovered that fan wasn't quite on properly. On the AC pulley the belt was one notch off centre. As mentioned above, make sure the belt sits properly on each pulley.

There is another old fashined way of stopping screeching. Crayon wax based.

Gilly · #6 11-23-2006, 06:24 PM

Gary: The tensioner for the AC pulley has 2 flat spots on it to put an open-end wrench on, to tighten the belt, then tighten the pivot bolt with the other. If you don't totally loosen the pivot bolt, you should be able to tighten the belt, have the tensioner stay in place reasonably well while you then tighten the bolt. I think the flat spots on the tensioner are around 18-20mm across the flats IIRC.
Gilly

Gary Ganaway · #7 11-23-2006, 07:47 PM

Thanks Gilly..I'm going to give it another shot with your advice although I checked it today with the climate control engaged and had no noise when compressor kicked on.

Spook74 · #8 11-24-2006, 10:01 AM

Quote:

Originally Posted by Gilly

Gary: The tensioner for the AC pulley has 2 flat spots on it to put an open-end wrench on, to tighten the belt, then tighten the pivot bolt with the other. If you don't totally loosen the pivot bolt, you should be able to tighten the belt, have the tensioner stay in place reasonably well while you then tighten the bolt. I think the flat spots on the tensioner are around 18-20mm across the flats IIRC.
Gilly

Gary,

If your tensioner is like the ones on my 87 300SDL or my 92 400E, the tensioner is separate, and you DO need to loosen the center bolt before adjusting the tensioner pointer to between the two center lines. (If you don't loosen the bolt, the steel adjusting plate flats will wear into the aluminum tensioner shaft flats, or the adjusting bolt will bend, and you'll never get it tightened up.) The pointer was missing on my 400E, but they can be replaced for a few $$.

FWIW, I had to replace the tensioners on both cars for belt squeal. The active element is a rubber "donut" inside the tensioner that gets torqued across, and tears with age. Like the rest of the rubber in these old cars, it is nearing the end of its service life. The manual includes a procedure for testing the tensioner by mounting it in a vice and deflecting it. Bad ones won't come back to the zero position.

If it is still good, and the aluminum shaft flats are worn, you might be able to flip the adjusting plate over and trade places with a spacer that sits behind it, so that it bears on an unworn section. Two bits says the rubber is gone though.

Gerry

Gilly · #9 11-24-2006, 05:45 PM

Gerry
This is a 117 engine (or is it 116?) and has seperate V Belts on everything, no tensioners, just tighten the individual components, or in the case of the AC belt it does have a tensioner pulley, but not one like you're thinking of.
Gilly