What happens to spring brakes when air pressure is removed?

When air pressure is removed from a braking system equipped with spring brakes, the springs that are part of the braking mechanism come into play. Specifically, the loss of air pressure causes these springs to engage, which applies the brakes automatically. This is an important safety feature designed to prevent unintended vehicle movement when there’s a loss of air pressure, typically linking the operation of the spring brakes to the air system in such a way that, without air, the brakes remain engaged. This action helps secure the vehicle in place until the air system is restored or the brakes are manually released, ensuring the safety of the driver and others on the road.