What should the air pressure gauges in a dual air brake system indicate while the engine is running and the system is fully charged?

Question: What should the air pressure gauges in a dual air brake system indicate while the engine is running and the system is fully charged?

Answer options: ✅ Both gauges should show similar pressures, typically between 700 kPa (100 psi) and 900 kPa (130 psi).

• The primary gauge should be significantly higher than the secondary gauge.
• One gauge should read approximately 60 psi (414 kPa) and the other 120 psi (827 kPa).
• Both gauges should read zero when no brakes are applied.

Correct answer: Both gauges should show similar pressures, typically between 700 kPa (100 psi) and 900 kPa (130 psi).

Explanation: In a dual air brake system, both the primary and secondary air pressure gauges should register similar pressures, typically within the normal operating range of 700 kPa (100 psi) to 900 kPa (130 psi) when the system is fully charged and the engine is running.