What are slack adjusters?

Slack adjusters are crucial components in the braking system of heavy vehicles. They serve as lever arms that connect the brake chamber's push rod to the brake shoes. When the driver applies the brakes, the air pressure in the brake chamber pushes the push rod, which in turn activates the slack adjuster. This mechanism ensures that the brake shoes are applied with the correct pressure against the brake drum, allowing for effective braking.

As wear occurs in the brake shoes, the slack adjusters compensate for this by adjusting their length to maintain the proper distance between the shoes and drum. This automatic adjustment is essential for optimal braking performance, as it helps prevent brake fading and ensures that the system operates effectively over time.

Other components mentioned, such as a type of tire pressure gauge, mechanisms to engage the emergency brake, or valves controlling air flow, do not fulfill the specific function of synchronizing the braking action with the wear of the brake components, which is the primary role of slack adjusters.