Belt tensioner M102.982 engine
 

Hello there,

I am replacing the polybelt damper strut on my W124 230. I removed the tensioner pulley to reveal the button headed torx screw behind it that secures the upper mounting bush on the damper to the tensioner bracket. In undoing this torx fastener, I mangled it and had to dremel it out.

It now seems from looking at the CD-ROM in the local dealership as though this was not the original fastener and the replacement bolt is (according to M.B.) an M6 bolt with a hex head. This cannot be right, as there is not enough clearance behind the tensioner pulley to accommodate the hex head.

My question is: can any of you good people out there with 190s (same engine) or 2.3 230s tell me how the upper (threaded end) of the belt damper attaches to the tensioner assembly? The bottom end is self explanatory. There is nothing in Haynes and the US CD-ROMs don't cover this model.

Baffled, but in hope,

Krolroger

I don't know if you have seen this image, it might help.

Haasman

Thank you very much for that. There must be an early and a later modified arrangement for the belt tensioner damper, and I guess that I've been given part information for the earlier one in error. The image still doesn't show the fastener, but it won't be a problem to locate a suitable high tensile item.

I realized I still had an old setup in the garage.

I looked at the shock and at the top end, on one side, there is a recessed hex head side that is chamfered. It looks like there is a specific nut that fits in there so it can be held to the bracket.

Oddly the illustration above doesn't show it.

Hope this helps

Haasman

Thanks for the input.

Yes, I'd noticed the hex recess in the top end of the shock, but I'm missing any sort of nut that would fit in there, and MB have no information that suggests that one was ever installed. Perhaps the damper has more than one vehicle application.

I think I've ordered the correct replacement bolt (MA001 990 01 12), though I have my doubts. I could just source a button headed M6 torx bolt and a nyloc nut.

Cheers,

Krolroger