Which of the following is a critical step after checking for air leaks?

After checking for air leaks, testing the braking response is a crucial follow-up step. This step is essential because it ensures that the air brake system is functioning properly. A well-functioning air brake system relies on adequate air pressure and a proper response from the braking components. By performing this test, a driver can verify that the brakes engage and release smoothly, confirming the integrity of the air brake system and its effectiveness in safely stopping the vehicle.

This step is fundamental to ensure that any potential issues or malfunctions can be identified before they lead to unsafe driving conditions. It also helps the driver become familiar with how the brakes respond under different conditions, which is vital for safe operation.

While inspecting wheel bearings, releasing service brakes, and adjusting brake shoes are also important maintenance activities, they are not directly related to confirming that the air brake system is functioning properly after checking for leaks. Testing the braking response is the specific step that directly assesses the air brake system's readiness for safe operation on the road.