In the past 4 months I have had failures of (we assume original) ignition lock/steering lock assembles for both a 129 as well as a 124 series. That's not the annoying part.

During the repair of both vehicles my independent mechanic ordered the replacement ignition lock/steering lock/key assemblies directly from the Mercedes dealer to avoid quality control issues. He ended up ordering three assemblies from the local dealer for the 1992 500 SL. and even the last one is hanging up (began within days of installation) now and will not allow you to turn it all the way off or it will remain locked in the off position and require substantial fidgeting to get it to turn. One ends up leaving the key in position one and locking the door with a separate key. That was the best of three new replacement switches ordered directly from the Mercedes Dealer, and which came in Mercedes boxes, with Daimler/Benz embossed on the assembly. Then my 1992 400E followed suit and the ignition key locked in the assembly and would not allow any rotation. as the steering was also locked along with the automatic shift in park, I had to have the car towed (from the rear) to the shop. We are now on the third new ignition / steering lock assembly from the Mercedes dealer, and it none of them will work right out of the box. That is six out of six defective ignition lock assemblies supposedly coming right from Mercedes (so says the box and the embossing on the part). There is another 124 (320E wagon) sitting in the parking lot unable to move because it has suffered the same fate...a brand new ignition lock assembly that get's installed and fails withing a few cycles.
That is seven out of seven failed, new and very expensive to repair parts, which have been shipped as genuine Mercedes parts from the dealer.

Have any of the rest of you been experiencing the same thing? I am thoroughly pissed and disgusted with this kind shoddy workmanship from a company that portrays itself as a paragon of excellence. NOTE THESE WERE NOT ORDERED AS CHEAP "ALTERATE SOURCE" AFTERMARKET PARTS, BUT RIGHT FROM THE LOCAL MERCEDES DEALER.