Ford Bronco Drum Brake Self-Adjuster Operation Diagram - Star Wheel Action

This schematic illustrates the operation of a drum brake self-adjuster mechanism in three sequential panels: 'No Braking', 'Braking in Reverse', and 'Brakes Released'. Each panel shows a cross-sectional view of a drum brake assembly with an enlarged inset of the star wheel adjuster. The first panel identifies the key components: anchor pin, secondary shoe, primary shoe, guide, cable, return spring, self-adjusting lever, star wheel, and lever, with an arrow indicating the front of the vehicle. The second panel shows drum rotation direction while braking in reverse, illustrating how the shoes shift with the rotating drum and how the cable pulls the self-adjusting lever up over the star wheel against the return spring. The third panel shows the mechanism after the brakes are released, with the return spring pulling the self-adjusting lever back down, rotating the star wheel one notch and thereby lengthening the adjuster to compensate for shoe lining wear. Figure reference numbers H9815-A, H9816-A, and H9817-A identify each illustration. A reader can learn the names and positions of the self-adjuster components and understand why drum brakes self-adjust when braking in reverse.