How can slack adjusters be adjusted?

Answer: C — Manually or automatically

Slack adjusters can be adjusted in both manual and automatic ways, making the option that states they can be adjusted manually or automatically correct. Automatic slack adjusters are designed to adjust themselves as the brakes are used, compensating for wear on the brake shoes and ensuring proper brake function without the need for manual intervention. This feature helps maintain optimal brake performance over time. On the other hand, manual slack adjusters require the driver or technician to physically adjust them using tools. Drivers should periodically check and manually adjust slack adjusters, especially if they notice issues with braking performance, to ensure safety and compliance with regulations. Being aware of how slack adjusters can be adjusted is crucial for maintaining the effectiveness of the air brake system in commercial vehicles. This understanding helps ensure that brakes are functioning properly, preventing potential safety hazards on the road.