Pennsylvania CDL Practice Exam

A defect related to the leaf springs that can result in a vehicle being classified as "out of service" is the missing or broken leaves in any leaf spring. Leaf springs are crucial components in a truck's suspension system, designed to carry the vehicle’s weight, absorb shocks from the road, and maintain tire contact for stability.

When any of the leaves in a leaf spring assembly are missing or broken, it compromises the suspension system’s ability to function correctly. This can lead to issues with load stability, increased tire wear, and can even affect braking performance by altering the vehicle's center of gravity. Safety regulations specify that such conditions must be addressed before a vehicle can be deemed safe for operation on the road. Thus, any missing or damaged components in a leaf spring directly impact the vehicle's safety and operational integrity, leading to an "out of service" designation until repaired.

In contrast, while items like a cracked steering arm, leaking shock absorbers, or broken U-bolts are also serious defects that can affect vehicle safety, they do not specifically pertain to the leaf spring system. Each of these components can contribute to overall vehicle control or suspension effectiveness, but missing or broken leaf springs are considered more critical due to their direct role in