Air Brake Maintenance & Troubleshooting Flashcards

What causes glazed brake linings and how does glazing affect braking performance?

Answer: Overheating from excessive braking — creates a hardened, low-friction surface that reduces stopping power

Overheated brake linings develop a glassy, hardened surface with significantly reduced friction coefficient, weakening braking force.

What is the most common cause of air brake system failure?

Answer: Air leaks that allow system pressure to drop below safe operating levels

Air leaks are the leading cause of air brake failure because even small leaks can eventually reduce pressure below the minimum needed for safe braking.

How can you detect an air leak in the brake system during a pre-trip or static inspection?

Answer: Listen for hissing sounds and watch the pressure gauge for unexplained drops with engine off

Air leaks produce audible hissing sounds and cause measurable pressure drops visible on the dash gauge when the engine is not running.

You notice the air pressure gauge dropping slowly while the vehicle is parked with the engine off. What does this indicate and what should you do?

Answer: This indicates an air leak that must be found and repaired before the vehicle is operated

Pressure should hold steady when parked; a slow drop confirms air is escaping through a leak that must be repaired before safe operation.

What problems does water accumulation in air tanks cause, and how is it prevented?

Answer: Corrosion of internal components and freeze-ups in cold weather — prevented by draining tanks daily

Water condenses in air tanks and causes internal corrosion and can freeze in cold weather, blocking air lines and valves.

What is the function of the air dryer in the air brake system?

Answer: To remove moisture and contaminants from compressed air before it reaches the tanks

The air dryer filters water vapor and contaminants from compressed air, protecting tanks, valves, and brake components from corrosion and freeze-ups.