Michigan State Brakes Certification Practice Exam

The process of adjusting disc-drum brakes typically involves a sequence that ensures proper function and safety. Releasing the parking brakes is an essential first step because it allows the rear drum brakes, which often rely on the parking brake mechanism, to be adjusted without undue tension that could lead to inaccurate measurements or adjustments.

When the parking brakes are engaged, they can hold the rear brake shoes in a position that does not reflect their true resting state. By releasing the parking brake first, the technician can ensure that the brake shoes are fully relaxed, leading to a more accurate adjustment of the rear brakes. This helps provide even brake performance and prevents premature wear or potential failure of the braking system.

The other considerations regarding adjusting the front brakes, simultaneous adjustments, or focusing solely on service brakes do not address the necessity of the parking brake’s role in the adjustment process, which could lead to suboptimal brake performance or safety issues.