In which component is asbestos often found?

Asbestos was commonly used in the manufacturing of brake pads because of its heat resistance, durability, and ability to reduce friction. In high-performance braking applications, these properties were beneficial as they enhanced the effectiveness of the brakes while also providing thermal stability. As a result, many older vehicles may have brake pads that contain asbestos material.

In contrast, the other components listed do not typically contain asbestos. Brake rotors are made from metal and composites that can withstand significant stress and heat but do not require asbestos for their effectiveness. Wheel bearings, which facilitate the rotation of the wheel while supporting load, are also made from metal and do not have a need for asbestos. Lastly, brake lines, which are involved in transmitting fluid pressure, are constructed from rubber or metal tubing and again, have no asbestos content. Thus, brake pads stand out as the correct answer due to the historical use of asbestos in their manufacturing process.