1997 S500 rear flex disc mystery

[bolomiester]

The car has been vibrating more as time goes on so I'm replacing the flex discs. When I took the rear disc out I found another part sandwiched between the drive shaft and the flex dics. It's an original Mercedes part "A1404110347" and while the flex joint looks a little cracked, this part is very much past prime and is most likely the source of most of my vibration. I can't find this part anywhere including the dealer, and it's not part of the "rear flex disc kit" from any supplier I can find. Plus no one I've talked with has ever seen or heard of it. Can anyone tell me what the deal is? Can I just leave it out? The part is pictured below.

[Frank Reiner]

That appears to be a torsional vibration dampener, usually found between the transmission output flange and the forward section of the driveline.

[bolomiester]

Yep, to my eyes that's what it looks like but it's in the rear between the end of the drive shaft and the flex joint.

[Frank Reiner]

Originally Posted by bolomiester

Yep, to my eyes that's what it looks like but it's in the rear between the end of the drive shaft and the flex joint.

That was understood from the first post.
A search of the P/N suggests that that is the original part and location for the model.

[bolomiester]

I've searched for the part number everywhere I can think of but it doesn't show up. I also called my local dealer and he says the part number doesn't exist and that he sees no such part on the drawing. In the drawing the rear of the drive shaft bolts directly to the differential. A photo of the part number is below, and it does have the Mercedes "Star" on it so it's an original part, and it fits where it's installed.

[anziani]

I checked with Mercedes of Atlanta and then googled the part number. You are right. It doesn't exist! Why don't you try MBUSA and see if they can help. Will probably need the VIN. Have you looked in EPC with your VIN number to see if it was something special for your particular car?
Anziani
'97 CL600 51K

[Zulfiqar]

I have also looked for this item but never could find it - I was looking for it when I was replacing flexdiscs on a W124 (early 300E)

I just left it out and it had no affect on the driveline.

If you are sensing vibration then its a better idea to look at the center bearing and the U joint in the shaft, the U joint is still using the same grease that was put in in 1997.

To replace the U joint - some members have found local to them shops that would change it after milling some grooves. I have not found any shops yet, All of them say they will have one shipped in from a remanufacturer or rebuilder.

[bolomiester]

We finally decided the strip all the rubber off that extra part that was between the drive shaft and rear flex disc. Then put it back together the same way it was. We also changed the front disc. When road tested the vibration was much better but not perfect. However, the rear tires were badly worn so I had them replaced and now the car is silky smooth all the way up 95!

I had the car aligned when I put tires on about 30,000 miles ago and the front tires still look very good, but the rears had steel showing on the inside edge and were worn very unevenly!

I'm looking for a good alignment shop in the Rockford, Illinois area. Can anyone give me a recommendation? I don't have a lot of confidence in the shop that did it last time. Update: I called a number of shops that said they couldn't do it. The local dealer could but not for two weeks, but recommended Archer Alignment in DeKalb, Illinois. They can do a four wheel alignment for me on Thursday. Cost, a little under a hundred.

Thanks!

[Zulfiqar]

if your rears are wearing in on the inner side on a W140 its a good idea to check the camber struts in the rear suspension and also check the subframe mountings. Regarding the vibration, did you check the universal joint in the driveshaft for notchiness?