Why is it a major taboo to engage the clutch before braking in second gear?

[McKhloe]

Engaging the clutch before braking in second gear is a major taboo because when the clutch is depressed, the engine speed rapidly drops to idle, and the total vacuum in the intake manifold decreases, significantly reducing the assistance from the vacuum booster, thereby increasing the braking distance. Here is more relevant information: 1. The correct approach: Release the throttle first, use the front brake to gently apply pressure, allowing the speed to drop quickly, then combine with the rear brake to control the speed. Once the speed drops to a reasonable range, pull the clutch to shift gears. 2. Consequences of pressing the clutch before braking at high speed: (1) Loss of engine braking, leading to longer braking distances (this could be fatal at high speeds). (2) Relying solely on brake pads for braking increases wear on the brake pads. (3) During deceleration, the engine needs to burn fuel to maintain idle, resulting in higher fuel consumption.