Final answer:
The brake bleeder valve is used to remove air from the wheel cylinder after repairs, ensuring that the brake lines contain only brake fluid for proper functioning.
Step-by-step explanation:
The brake bleeder valve provides a means of removing air from the wheel cylinder after repairs. When servicing or repairing brake systems, it is crucial to remove any air that may have entered the brake lines or wheel cylinders. Air in the brake system can lead to a spongy brake pedal and decreased braking efficiency, which is a serious safety concern.
The brake bleeder valve is opened during the bleeding process, allowing brake fluid and air bubbles to be expelled, ensuring that only brake fluid remains in the brake lines and wheel cylinders. This process is usually carried out with the assistance of another person who depresses the brake pedal during the procedure.