What happens if the slack adjusters are not functioning properly?

When slack adjusters are not functioning properly, it can lead to a situation where the brakes may fail to engage effectively. Slack adjusters are critical components of the braking system, especially in vehicles with air brakes. They are designed to automatically adjust the brake shoes to maintain the correct distance from the drum. If these adjusters are not working correctly, the brake shoes may not come into contact with the brake drum when needed, causing a significant reduction in braking force or complete brake failure. This could result in dangerous situations, such as not being able to stop the vehicle in time, leading to accidents.

The other options do not relate directly to the brake system's primary role. Fuel efficiency can be influenced by numerous factors, including engine performance and tire pressure, but it is not directly linked to the slack adjusters. Vehicle speed being affected by slack adjusters would only be true in the context of braking effectiveness, and power steering operations are separate from the braking system. Therefore, the primary concern with malfunctioning slack adjusters is their impact on braking performance.