Commercial Driver’s License (CDL) Test 2025 – 400 Free Practice Questions to Pass the Exam

The air compressor is the component that helps to boost the air pressure in a brake system. In a commercial vehicle, the air compressor pumps air into the storage tanks of the brake system, ensuring that there is enough compressed air available to operate the air brakes effectively. This boost in air pressure is crucial for the brakes to function properly, as they rely on this pressure to apply the brakes when the driver engages the braking system.

An air dryer is used to remove moisture and contaminants from the compressed air to prevent freezing and corrosion, but it does not directly boost the air pressure. A brake booster is typically associated with hydraulic systems, where it amplifies the force applied to the brake pedal, rather than serving to increase air pressure in an air brake system. A pressure regulator helps to maintain the correct pressure in the system but, again, does not actively increase that pressure. Therefore, the air compressor plays the essential role of increasing air pressure in the brake system.