What Causes the Thumping Sound Near the Rear Wheels of a Car?

[Delilah]

The causes of a thumping sound near the rear wheels of a car are: 1. Issues with the shock absorber, spring, or the rubber bushings at the junction of the spring and shock absorber; 2. Loose screws in the chassis, rear axle, or tires—check and tighten all potentially problematic screws; 3. Hardened dust covers rubbing over time, producing noise. Shock absorbers can be categorized based on damping materials into hydraulic and pneumatic types, with another variant being adjustable damping shock absorbers. Shock absorbers primarily function to dampen oscillations from spring rebound after absorbing shocks and to mitigate impacts from the road surface. When traversing uneven roads, while the suspension springs filter out road vibrations, the springs themselves still undergo reciprocating motion, and shock absorbers are designed to suppress this spring oscillation.