geez.
yeah, that's the one, the 17mm bolt. it is now round, for what it's worth. i figured it didn't matter much at this point, since the idea was to get a whole new bracket and replace the broken one. who knows what would have been left to thread into in the old bracket, but anyway, now it's toast.

problem is, we had to give up on trying to dismantle the '79 at the junkyard, because we couldn't see how to get at the thing without taking off the crank pulley, and we had no allen keys.

this is an '83 300TD. it was bought for a mere $200, at 257,000 mi. a baby, really, for a MB diesel. in pretty good shape, all it seemed to need was a battery. then the alternator light was coming on at the dash, and after switching out the regulator brush pack , it kept happening (light would glow faintly, and increase in brightness with revs. charging voltage seemed weak at 13.2V max.) having a spare alt., we wanted to change it out, and it led to all this.

if the bracket is aluminum, it must be galvanic corrosion at work here. i have never seen anything like it. anyway, given the low initial price of this car means it would be a tough decision to take it to a garage for repairs. i guess welding the bracket back together makes some sense - at least it could be removed from the car at "leisure" in teh driveway. i may still try taking off the AC compressor to see if an alternator could be mounted there instead.

thanks for all the help!

Vytas