I just came inside from fixing it. It turns out that you can remove the belt from the mechanism by unreeling it all the way, pushing the end backwards through the spindle and removing a plastic pin that "fattens" the belt enough to prevent the belt from sliding through the spindle. It will be obvious what I'm talking about if you decide to take yours apart. I was able to retain my tensioners by swapping non-broken belts onto the mechanisms with tensioners.

You will probably want a 2nd set of hands to keep the mechanism from rewinding once you remove the belt. I was able to do it alone, but it would have been easier with 20 more fingers.

-Tad

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1995 G320
2003 C230 Kompressor Coupe
2005 ML500
2007 ML350