How do automatic slack adjusters work?

Automatic slack adjusters are devices used in vehicle braking systems, particularly in air brake systems, to maintain optimal brake shoe clearance. They automatically adjust the position of the brake shoes relative to the drum as the brake linings wear down, ensuring consistent braking performance. The mechanism typically includes a ratchet and pawl system that engages during brake application, allowing for incremental adjustments without requiring manual intervention. This helps in reducing brake fade and enhancing safety by ensuring that the brakes remain effective over time.