FYI Broken M103 camshaft rotor adapter distributor rotor bracket 1031580840
 

Took my 101k mile, 1991 300SE in to have the u shaped seal replaced. Decided to have the shop replace the seal just in case they might notice something important. They did. The camshaft rotor adapter a.k.a. distributor rotor bracket part number 1031580840 was cracked and about to fail. As you can see in the attached photos, just a small piece of metal was holding the pieces together and would have soon failed, separating the rotor from the camshaft.

If you pull the rotor, might want to check out this part.

I know there was an update/change in materials, but I thought that was only pre-88 models. Maybe someone put the wrong one in yours?

Shop believed it was the correct part. Seems this has happened before. http://www.peachparts.com/shopforum/showthread.php?t=141399

Perfectly normal - even the trees rust down there in Houston!
Guess I'd better check mine; been pretty humid up here in Dallas lately too.

DG

My car died on the road this past weekend and got towed in. 1992 190E 2.6. I got a call from the mechanic this morning and he says the end of the camshaft broke off. I thought that sounded a bit unlikely, so I surfed until I found this thread. I'm going to look at it after work, but what are the odds that it broke the actual camshaft??? I think this joker is setting me up for a scam and a big bill.

Could be...but he might just not know these cars and know its not actually the cam. Tell him its an adapter and you have read its a common issue. The part is ~$60 and shouldn't be more than 1-2hrs of his time assuming he has trouble getting the broken piece out. Anything over a $250 estimate walk away for sure and take it to a European shop who has experience with the M103.

Even the stubborn ones will come out pretty easy with a little know how. Thread a tap into the piece left in the camshaft, 9.0X1.0 IIRC. Then grab the tap with vice grips and give it light taps with a small ball peen hammer. Shouldn't take more than 5 mins. before you're ready to put it back together. Don't he-man down on the bolt either, it has a relatively low torque.