Some vehicles may exhibit a knocking noise from the rear of the vehicle when driving over a road bump. Upon inspection of the rear suspension, the bump stop (bound stopper) of the rear shock absorber is coming out of the mounting rubber.This is caused by the adhesive surface of the mounting rubber bracket having inadequate roughness opposite to the bound stopper and the bracket shape being inapporopriate to have sufficient holding force. The bound stopper may come out under any of the following conditions: When the bound stopper shrinks during cold weather  When the bound stopper expands during cold weather after absorbing water  When the shock absorber moves down after freezing over in between the shock absorber and the dust cover.
