Air Brake Practice Test

Which statements about dual air brake systems are true?

1. They have a single air tank

2. They have primary and secondary systems

3. They only operate on electric power

4. They do not require maintenance

The correct answer is: They have primary and secondary systems

Dual air brake systems are designed with both a primary and a secondary system to enhance safety and functionality. This design ensures that if one system fails or experiences a drop in air pressure, the other system can still function effectively, thereby maintaining braking capability. The primary system typically operates the rear brakes, while the secondary system operates the front brakes or vice versa, providing a backup to prevent complete brake failure. This redundancy is essential in heavy vehicles where stopping power is critical for safety. In contrast, a single air tank, which is mentioned in one of the options, is not representative of dual systems since these setups have multiple tanks to support the primary and secondary systems. Additionally, dual air brake systems do not operate solely on electric power; they are pneumatic systems that rely on compressed air. Lastly, while maintenance is necessary for dual air brake systems to ensure they function properly, it's incorrect to say they do not require maintenance, as regular checks and service are critical for safety and performance.