I can feel it rear driver side wheel jumps violently when the wheel is driven over some kind of manhole on the street at a normal speed, and of cause it makes a loud noise too. The damper has been replaced with a new one to try to solve it. It didn't fix it much. I am leaning over a weaken coil spring. However, the car is only 78000 km, and people have been saying coil springs hardly fail. How should I diagnose the problem further?