Manitoba Airbrake Practice Exam

A "leak test" is performed on a brake system primarily to ensure that no air is escaping from the system, which confirms its integrity. In air brake systems, maintaining the correct air pressure is crucial for effective braking performance. Any leaks can result in a loss of pressure, leading to insufficient braking ability, which poses significant safety risks. By conducting a leak test, technicians can identify any potential issues in the air lines, fittings, and other components of the brake system.

The other options do not pertain to the purpose of a leak test. Checking tire pressure, determining brake pad thickness, and measuring air temperature are important maintenance tasks, but they do not relate to verifying the integrity of the air brake system itself. The focus of the leak test is specifically on preventing air loss, thereby ensuring reliability and safety in the operation of air brakes in vehicles.