The Audi A4L (B8) car with a mileage of about 103 thousand km in 2010. When the car bumps along the road, it has abnormal noise on the front suspension. Fault diagnosis: the components that cause abnormal noise are as follows. (1) whether the shock absorber is normal. (2) the upper control arm is normal. (3) the lower control arm is normal. (4) whether the semi - axis and the inside and outside cages are normal. (5) the balance rod rubber sleeve and the small connecting rod are normal. (6) whether the direction machine and the head of the pull rod are positive. (7) whether the engine mats are normal. On the level ground, the human body swayed the body and found the right front abnormal sound more obvious. In order to check the above components, the right front balance bar linkage was degumming. Troubleshooting: changing the balance rod and connecting rod.