What is the first step to check the free play of manual slack adjusters on s-can brakes?

Answer: C — Park on a level ground and chock the wheels

To check the free play of manual slack adjusters on S-cam brakes, parking the vehicle on level ground and chocking the wheels is crucial for safety and accuracy. Level ground ensures that the vehicle is stable, preventing any unintended movement, which could occur if the vehicle were on an incline. Chocking the wheels adds an additional layer of safety, ensuring that the vehicle remains securely in place while you inspect the slack adjusters. By creating a stable work environment, you can safely measure the free play and make any necessary adjustments. This method is standard practice to ensure accurate readings and safe operation when working on brake components.