My S4 has started making a knocking sound along the n/s when i go over small bumps etc in the road. I know there are a few bushes on the suspension, but does anyone know which ones would bew the likely culprit/s?? Also, when i jack up the car, i cant really ascertain which bushes are worn. Is there an easy way of checkin them?? Dan I've checked the engine gaurd and the exhaust...it's not them.