Which of the following is a defect in a suspension system?

A defect in a suspension system is highlighted by the presence of leaking shock absorbers. Shock absorbers are crucial components that help control the compression and rebound of the vehicle's springs, ensuring a smooth ride and stability while driving. When shock absorbers leak, they lose their ability to effectively dampen the bounce of the vehicle, which can lead to a rough ride, decreased handling capability, and increased wear on other suspension components.

The condition of the other options indicates that the suspension is functioning properly. Leaf springs that are in perfect working condition contribute to the overall stability and load distribution of the vehicle. Stable spring hangers suggest that the springs are securely mounted and functioning as intended. Well-maintained air suspension systems are designed to provide a comfortable ride and compensate for varying load weights, indicating that this part of the suspension is also in good shape.