What is a crucial step before inspecting the master cylinder fluid level in power master-type systems?

Before inspecting the master cylinder fluid level in power master-type systems, it's essential to depress the brake pedal multiple times. This action serves a specific purpose: it helps to build up brake system pressure. Many modern vehicles with power brake systems maintain different fluid levels based on whether the brake pedal is activated or not due to the position of the master cylinder and the amount of fluid displaced by the piston movement.

When the brake pedal is depressed, the master cylinder pressurizes the brake system, which can also affect the fluid level in the reservoir. Therefore, checking the fluid level while the system is at pressure provides a more accurate assessment of the actual fluid level required for proper brake function. Ensuring the system is pressurized makes it possible to verify if the fluid level is adequate for the system to operate correctly, preventing potential safety issues related to insufficient brake fluid.