I have a decent vibration when I drive my 91 300E once it hits 25-35 it starts vibrating, I took it to a tire place right now to get the wheels rotated and the front wheels balanced which did nothing. I jacked up the car to inspect the flex disc in the rear (where it feels like it's coming from) and there is a bolt missing on the rear flex disc, could this be the culprit? Could it be off balance?

__________________
76 MG Midget
78 Datsun 280Z
86 Peugeot 505
01 Subaru Outback

“Owning a car is like owning a dog. Every now and then, it craps on the carpet — but it’s still your dog.” - Jeremy Clarkson

Most definitely. Not only is there an imbalance due to the missing bolt, but the flex disc can also move around a bit there.

__________________
Erich Loepke
2010 Ford Focus
Currently Benz-less

theres metal inserts in the flex discs. Check them for play. I usually replace them once I see dry cracks in them.

__________________

99 Jetta Mk3
07 Jetta Mk5
89 300E W124
10 E 350 W212
08 C300 W204
Benz's aren't mine

Replacement bolts/nuts should come with the new flex disc. Be sure to check the condition of the front flex disc too. You will need large open end wrenches to loosen the driveshaft coupling so the driveshaft will telescope to allow sufficient clearance for rear flex disc removal. If for some reason the driveshaft halves separate be sure to reassemble using the match marks or the driveshaft may be out-of-balance. It's likely that you will need to lower the exhaust system to work on the flex disc and driveshaft coupling. This is a DIY job, but time consuming ... at least when I did it.

__________________
Fred Hoelzle

I'm suprised to hear the vibration starts so low speed.

Are your wheel brgs tight? Any play in the idler arm? Motor mounts good?

For God's sake, don't wait to fix it. That can fail with rather dire consequences.

__________________
-tp


1990 300SE "Corinne"- 145k daily driver - street modified differential - PARTING OUT OR SELLING SOON - PORTLAND OR. AREA - PM ME FOR DETAILS
1988 560SEL "Gunther"- 190K passes anything except a gas station
1997 S420 - 265k just bought it with a rebuilt trans. Lovely condition