What could cause you to crash if the level is allowed to get too low?

Explanation: You should carry out frequent checks on all fluid levels but particularly brake fluid. As the brake pads or shoes wear down, the brake-fluid level will drop. If it drops below the minimum mark on the fluid reservoir, air could enter the hydraulic system and lead to a loss of braking efficiency or even complete brake failure.

Category: Safety and your vehicle

References: Highway Code: Page 130