For vehicles with vacuum brakes, what is the maximum reservoir depletion when the engine is stopped?

The maximum reservoir depletion for vehicles equipped with vacuum brakes when the engine is stopped is 40%. This means that after the engine ceases to run, the reservoir pressure can decrease to 40% of its maximum capacity before the brakes are compromised. Vacuum brakes rely on the vacuum generated by the engine to function effectively; when the engine stops, the vacuum begins to diminish. A depletion of up to 40% indicates that there is still a substantial amount of vacuum left in the system, ensuring that the brakes continue to operate adequately for a certain time, providing the driver with a safety buffer. Understanding this aspect is crucial for effectively managing vehicle braking systems, especially in situations where the engine might fail or be turned off unexpectedly.