Practice question

How does a pneumatic air brake system (frenos de aire) operate on heavy commercial vehicles?

Water pressure generated by the radiator expands brake drums
An engine-driven compressor pumps compressed air into storage reservoirs; pressing the brake pedal directs compressed air into brake chambers, converting pneumatic pressure into mechanical clamping force on the wheels
Vacuum generated by the air conditioner pulls the brake shoes
Electric solenoids directly touch the tires

Answer: B — An engine-driven compressor pumps compressed air into storage reservoirs; pressing the brake pedal directs compressed air into brake chambers, converting pneumatic pressure into mechanical clamping force on the wheels

The correct answer is shown above. Try the full quiz for additional practice.