Bob,
A little war story on this part. Back in the early 80's when I was stationed in Germany, I had a 1970 280S. Loved that car--was a sheer pleasure to cruise down the autobahns and the engine could hardly be heard when I was stopped at a traffic light. It did have one problem though that took me a while to figure out. Every time I came to a stop , I would hear a thunk from the front end. I finally got under the car one day and took a good look at the kingpins--the source of the thunk was immediately obvious. I set about to fix the kingpins in my small backyard--having the car down for a while was no big problem since I had the current 230Sl as well. Ordered the top-end parts from the MB Torpedo Garage in Kaiserslautern and then started the disassembly and that's when my problems started. I didn't shear the bolt as you did, but try as I may, I could not remove that darn threaded pin. Years of lubricant neglect had literally "welded' that pin in. I tried a bolt remover, heat, a sledge hammer, a hacksaw, you name it! every day I went into work, I'd set about a new strategy to get that pin out. In utter frustration, I finally decided that my only recourse at that point was to do a complete remove and replace of the entire hub assembly. At that time the U.S.Air Force Base over in Sembach maintained a large Morale, Welfare and Recreation salvage yard of vehicles left behind by departing Serviceman who could not sell their cars-parts were there for the picking for next to nothing e.g. complete engines for less than $50.00 and the yard was loaded with 70's era MB sedans--wish that yard was still there--the base has been pretty much turned back over to the Germans as part of our drawdown and the yard is no longer there. I was able to get a part that appeared good readily and did the remove and replace. Next step was to get a front end alignment. Dropped it off and expected it would be ready the next day. When I went to pick it up the shop owner said he could not do the front end alignment because the kingpins on both sides were too worn! This front end wear was a common problem on all MB's of that era-- even the donor car had the problem. I only had a short time left in country and decided to just "live" with it. What I did learn from this experience is to make darn sure that the grease fittings on the kingpins on my 230SL are serviced regularly with a good quality grease. When it came time to do the front end on the 230SL as part of my restoration work, I had no problem doing either the dissaembly or the reassembly and all parts were still servicable! Bottom line--keep these front ends well greased! Good luck with your work on this.
George Des