What should be regularly checked to ensure the braking system remains reliable?

The reliability of a vehicle's braking system is paramount for safe operation, particularly for commercial vehicles that require a CDL. Regularly checking the condition of brake pads is essential because they are a critical component of the braking system. Brake pads wear down over time due to friction when the brakes are applied. If they become too worn, they can lead to decreased braking efficiency, which could result in longer stopping distances or even complete brake failure.

Maintaining the right thickness of brake pads ensures that the brakes can effectively clamp down on the brake rotors and provide the necessary stopping power. Inspections should include checking for cracks, excessive wear, and proper alignment of the pads within the caliper. Timely replacement of worn brake pads is crucial to maintain optimal braking performance and to prevent further damage to the braking system, such as warping of rotors or drum damage.

The other choices do not directly relate to the core function and safety of the braking system, making them less critical in the context of ensuring reliable brakes.