This bulletin applies to 2011 Mercedes-Benz C300 models. The strut-to-suspension strut tower bolt design has been changed. The bolt has been modified because of the improvement measures to the strut to tower. The new bolt can be recognized by its larger collar diameter. A new coating on the bolt also means that the tightening torque is slightly lower.
The original bolt collar measures 17.5 mm in diameter, while the new (and only replacement bolt available) measures 20 mm in diameter.
If the strut has been released from the strut tower, the bolt must be replaced if the previous, smaller-diameter-collar bolt was installed. Only the new version is now available as a replacement bolt.