Master Air Brake Systems: Take the Quiz Now!
Think you know if your truck has a dual air brake system? Prove it here!
This air brake quiz helps you practice what all air brake equipped vehicles share and how each part works. Review brake drums, reservoirs, pressure gauges, and dual systems, and get scored results to spot gaps before the CDL test. For more practice, try a CDL air brake practice test .
Study Outcomes
- Understand Core Components -
Recognize what all air brake equipped vehicles have by identifying parts like brake drums, valves, and chambers to ensure proper system awareness.
- Apply Pressure Gauge Functions -
Explain air brake pressure gauge function and interpret readings accurately for safe operation and maintenance of braking systems.
- Analyze Dual Air Brake Setups -
Determine if your truck has a dual air brake system by assessing its configuration and understanding how two-line systems enhance safety.
- Perform Safety Checks -
Conduct an air brake system safety check by following key inspection steps to identify leaks, pressure drops, and component wear.
- Evaluate Emergency Brake Readiness -
Assess emergency brake components and scenarios to ensure vehicles maintain stopping power under system failures.
Cheat Sheet
- Pressurized Air Supply -
All air brake equipped vehicles have an air compressor, air reservoirs, and pressure governor that maintain system pressure between 100 - 120 psi. A handy mnemonic is "C-R-G" (Compressor, Reservoir, Governor) to remember the core supply components. Proper maintenance, as outlined by FMCSA regulations, ensures reliable brake actuation and prevents moisture buildup.
- Air Brake Pressure Gauge Function -
The air brake pressure gauge monitors system pressure in primary and secondary circuits and warns drivers when pressure drops below 60 psi. For example, a dual-needle gauge shows both circuits in real time to help detect leaks early. Regular checks per SAE International guidelines prevent brake fade and ensure accurate readings on every trip.
- Dual Air Brake System Safety -
If your truck has a dual air brake system, it splits into two independent circuits - one for the front axle and one for the rear. A failure in one circuit won't disable the other, offering redundancy; remember "Two Circuits, Twice the Safety." Periodic leak-down tests, as recommended by NHTSA, verify each side holds pressure for at least two minutes.
- Slack Adjusters and Brake Drum Clearance -
All air brake equipped vehicles have automatic or manual slack adjusters to maintain proper shoe-to-drum clearance, typically around 0.04 in. Use a ruler to check that pushrod stroke doesn't exceed 1 in during a static test, per manufacturer specs. This simple check, endorsed by technical bulletins from industry leaders, ensures responsive braking.
- Spring/Emergency Brake Mechanism -
The spring brake chambers act as fail-safes, applying brakes mechanically if system pressure falls below 20 - 45 psi. To test, build pressure then shut off the engine and watch for spring engagement - verify it applies within the required pressure range. This feature, governed by FMCSA Part 393, safeguards against total brake loss.