Which of the following is NOT a part of the steering system?

The braking system and the steering system are distinct components of a vehicle's overall operational framework. The steering system is specifically responsible for guiding the vehicle's direction and includes crucial parts that allow for precise maneuverability. The steering wheel, power steering cylinder, and steering knuckle all play vital roles in this process.

The steering wheel is the primary interface for the driver to control the vehicle's direction. The power steering cylinder assists in making the steering easier by providing hydraulic or electric assistance. The steering knuckle connects the wheel to the steering system and allows the wheels to pivot for steering.

Brake pads, on the other hand, are part of the braking system, which is unrelated to steering. They are responsible for applying friction to the brake rotors to slow down or stop the vehicle. Therefore, while the other components function within the steering system, brake pads serve a different purpose entirely within the braking system, making them the correct choice for the option that does not belong in the context of the steering system.