Which component is NOT part of the steering system?

The brake pedal is not a component of the steering system; rather, it is part of the vehicle's braking system. The braking system is responsible for slowing down or stopping the vehicle, while the steering system is responsible for directing the vehicle's movement.

In contrast, the power steering cylinder, gear box, and steering knuckle all play essential roles in the steering process. The power steering cylinder assists with making the steering wheel easier to turn, the gear box translates the rotational movement of the steering wheel into movement of the wheels, and the steering knuckle connects the wheel to the steering system and allows for pivoting during turns. Understanding the distinct functions of these different systems is crucial for safe vehicle operation and maintenance.