What indicates a failure in the hydraulic leak test?

A failure in the hydraulic leak test is indicated when the brake pedal height drops. This is a critical observation because a drop in the pedal height suggests that there may be air or fluid leakage within the brake system, which can compromise the braking system's effectiveness. When the hydraulic system is functioning correctly, the brake pedal should maintain a consistent height under pressure.

Choosing brake fluid leakage as an indicator alone may not accurately define a hydraulic leak test failure since it may or may not cause a noticeable change in pedal height depending on the severity and location of the leak. Evaluating brake pad thickness is more related to the wear of braking components, while assessing fluid color is a part of routine maintenance but doesn’t directly measure hydraulic integrity. Thus, monitoring the brake pedal's response is a fundamental aspect of confirming a properly functioning hydraulic system.