What are the signs of a leaking air brake system?

A drop in air pressure or audible hissing sounds are indeed key signs of a leaking air brake system. When air pressure drops, it indicates that there is a loss of air somewhere in the system, which could be due to a leak. The audible hissing sound is often a direct indication of escaping air, which can come from damaged hoses, fittings, or seals within the braking system.

Monitoring air pressure is crucial, as the air brake system relies on adequate pressure to function properly. A decrease in this pressure can compromise the system's effectiveness, leading to potential safety hazards. Recognizing these signs early allows for timely maintenance and repairs, ensuring the braking system operates as intended for safe driving conditions.

The other options, while they can pertain to brake performance, are not direct indicators of an air leak. Increased brake pedal travel could suggest wear in components such as the brake pads or air supply issues but does not specifically point to a leak. Unusual noises from the brake pads may indicate issues with the pads themselves rather than the air system. Reduced braking effectiveness during tests can happen for various reasons, including issues unrelated to the air supply, such as brake adjustments or the quality of the brake pads, but again, this doesn’t directly signify an