CDL Air Brakes TestAir Brake System PartsEasy
A driver is conducting a pre-trip inspection on a commercial vehicle equipped with an air brake system. What is the primary purpose of the supply pressure gauges?
- ATo show the pressure at which the air compressor cuts in and cuts out.
- BTo measure the effectiveness of the anti-lock braking system (ABS).
- CTo indicate the pressure applied to the brake chambers during braking.
- DTo monitor the air pressure available in the primary and secondary air tanks.
Show answer & explanationAnswer & explanation
Correct answer: D. To monitor the air pressure available in the primary and secondary air tanks.
Supply pressure gauges are crucial for monitoring the air pressure in the vehicle's air tanks, ensuring there is sufficient air for safe braking. This allows the driver to confirm the system is adequately charged before operation.
Why the other options are wrong
- A. The cut-in/cut-out pressures are determined by the governor, and while indirectly related to tank pressure, aren't the primary reading of these gauges.
- B. ABS effectiveness is indicated by warning lights and system performance, not directly by supply pressure gauges.
- C. This describes the function of a brake application gauge, not a supply pressure gauge.
Supply Pressure Gauges
Gauges on the dashboard that display the current air pressure in the primary and secondary air storage tanks of a commercial vehicle's air brake system.
- Indicate available braking air.
- Typically one gauge for each tank (primary/secondary).
- Crucial for pre-trip inspections and continuous monitoring.
Memory trick: Gauges Guard Global Air Supply.