CDL Air Brakes TestDual Air Brake SystemsHard
Which of the following is NOT a characteristic of separate controls in a dual air brake system?
- AEach system has its own independent air lines to brake chambers.
- BEach system has its own foot pedal for brake application.
- CEach system has its own air pressure gauge.
- DThe foot pedal valve has internal sections for primary and secondary air.
Show answer & explanationAnswer & explanation
Correct answer: B. Each system has its own foot pedal for brake application.
While 'separate controls' implies independence, commercial vehicles with dual air brake systems typically use a single foot pedal that internally controls both primary and secondary air systems through separate sections of the brake pedal valve. Having two separate foot pedals would be impractical and unsafe.
Why the other options are wrong
- A. Separate air lines are a fundamental aspect of the dual system's independence and redundancy.
- C. Separate air pressure gauges are essential for monitoring the health and pressure of each independent system.
- D. The foot pedal valve (treadle valve) is a key component that separates air control for the primary and secondary systems internally, even though it's a single physical pedal.
Dual Air System Separate Controls
Separate controls in a dual air brake system refer to the internal independence of components like air lines, tanks, and pressure gauges, but typically utilize a single foot pedal valve with internal separation for brake application.
- Single foot pedal for driver input.
- Foot pedal valve has internal primary/secondary sections.
- Air tanks, lines, and gauges are separate.
- Ensures redundancy.
Memory trick: Separate parts, single step, safety's goal, no misstep.