What is the initial step when installing new brake tubes?

Answer: B — Always clean the inside of the new tube

When installing new brake tubes, the initial step should involve cleaning the inside of the new tube. This is crucial because any contaminants, such as debris, dust, or metal shavings, could enter the brake system and potentially cause malfunction, reducing braking performance and safety. Ensuring that the interior of the tube is clean helps maintain the integrity of the brake system and promotes effective operation right from the installation. While inspecting the exterior of the tube, measuring its length, and checking for any damage are also important steps in the installation process, they come after ensuring the cleanliness of the tube's interior. Cleaning is fundamental to prevent contamination during the installation, which is why it takes priority in the overall procedure.