What could possibly be the problem? flex disc? rear end?
 

Folks,

I am in dire need of advice and direction in trying to diagnose and eliminate an intermittent yet frequent shudder in a 2000 c230. To summarize, the shudder comes and goes intermittently. It seems to start in the center, underside of the car and resonate violently throughout the chasis and transfers to the steering wheel. It typically begins somewhere between 50 and 60 mph and continues at any speed above. I have had every, and I mean every steering, suspension, and brake component replaced and this problem still persists. The tires are brand new too (Yokohama Advan S4) and AMG wheels. As I continued my investigation, I noticed that the front flex disc appeared to have some of its fasteners separating from the semi-spherical notches that the washers slide in to. Is it possible that I have a damaged flex disc or u-joint? I am attaching several photos I took of the suspect fasteners/washers. I haven't begun to investigate rear end suspension problems. Could rear suspension component failure cause this type of shudder all the way through to the steering wheel? I am aimlessly searching for the cause and am running short on possibilities here. Any help would be greatly appreciated.

Thanks
http://www.peachparts.com/shopforum/picture.php?albumid=217&pictureid=1485

http://www.peachparts.com/shopforum/picture.php?albumid=217&pictureid=1484

http://www.peachparts.com/shopforum/picture.php?albumid=217&pictureid=1483

In the 2nd pic, the bolt appears off centre. There also seems to be a little surface rust - maybe just crud. And thirdly, these bolts look new, which makes me wonder, "what has been going on down there?" I suggest removing one of these bolts - preferrably the off-centre one - for a good investigation. If anything looks remotely not right, replace the flex disc. Check the rear disc as well.

Have you checked the carrier mount and carrier bearing? Have you removed or otherwise done anything with the driveshaft?

Dont forget to look at the center support and bearing.

I have no idea if this applies to MBs with flex discs, but as somebody else pointed out, those bolts look new, which means that the flex disc may have been replaced already. On some cars, if you put the shaft back on in any other manner than it was taken off, you can get big vibrations. On old cars with U-Joints, the fix was to take it off, spin it 180 degrees and bolt it back up.

I don't know if that positioning is a concern on your car or not. It does look like the driveshaft has bits of metal welded on for balance, though......

Just wondering if perhaps you need to spin the shaft........

Another note on flex disks is that all the bolts should be started and torqued evenly. If you torge one first it can unalign the shaft.