Mercedes-Benz W220 propshaft vibration and loose flange
What causes propshaft vibration in the W220?
The cause of the vibration can be the rear flex joint (rubber coupling) of the propshaft or its support bearing, whose rubber has torn. The vibration can be felt at a certain speed, for example under engine braking or light throttle. When the broken part is replaced, the vibration usually stops.
Why won't the propshaft flange bolts tighten properly?
The rubber of the flex joint can be in such poor condition that play is left between the flange and the joint. The play may show only in a certain position of the propshaft. In that case the joint must be replaced; tightening the bolts alone is not enough.
How is propshaft play checked?
In a two-piece propshaft the joint is in the middle at the support rubber. Play can be felt by twisting the parts in different directions, and the check is most reliable when the propshaft is removed and on a bench. Vibration can also be caused by a broken centre support rubber and the centring supports.