What Causes Chassis Noise on Slightly Bumpy Roads?

[Cooper]

Here are the specific reasons for chassis noise on slightly bumpy roads: 1. Disc brake malfunction: When driving at low speeds on flat roads, irregular intermittent noises occur near the wheel axle. The noise slightly intensifies with increased speed but remains unchanged during uphill, downhill, or turns. On uneven roads, the noise becomes louder, and pressing the brake pedal reduces or eliminates the sound. During inspection, rotating the wheels back and forth can reproduce the noise. This is caused by damage, deformation, or detachment of the disc brake's shoe support plate, damping spring plate, or guide plate, increasing the gap between the brake shoe and caliper bracket, leading to impact noises. Deformed parts should be repaired and detached parts replaced at a service station. 2. Front suspension ball joint failure: When driving at low gear on bumpy roads, continuous noise occurs near the front axle, intensifying with worse road conditions and higher speeds. Vigorously shaking the front of the parked vehicle produces noise. On smooth roads, irregular intermittent noises resembling metal cracking impacts occur. This is due to excessive clearance between the ball joint and its socket. Since the ball joint socket is a sealed structure and non-detachable, replacement at a service station is necessary. 3. Front wheel shock absorber failure: On smooth roads, slight noise can be heard from the front of the vehicle, worsening during sharp turns. Pressing down on the front of the parked vehicle to create rebound motion reproduces the noise, with intensity proportional to the force applied. The vehicle feels stiff and lacks elasticity. This usually results from driving on poor roads with inadequate maintenance, causing shock absorber oil leakage and damage. Depending on severity, repair or replacement at a service station is required.

[Jayden]

I've encountered similar situations where chassis noises are particularly noticeable on bumpy roads, mostly due to suspension component issues. For example, if the control arm bushings age and crack, causing increased gaps, you'll hear creaking sounds when going over bumps; if the stabilizer bar links' ball joints wear out and become loose, there will be distinct metallic clinking sounds as the wheels move up and down; and if the shock absorber top mounts crack, each compression will produce a thud. These rubber components tend to crack after five or six years, especially in vehicles frequently driven on rough roads. By the way, loose tie rod ends can also produce similar knocking sounds on bumpy roads—this needs immediate repair to prevent potential steering misalignment.