What is the role of the master cylinder in a brake system?

The master cylinder is a crucial component of a brake system, and its primary role is to convert the force applied through the brake pedal into hydraulic pressure. When the driver presses the brake pedal, the master cylinder compresses the brake fluid within it. This action creates hydraulic pressure that is transmitted through the brake lines to the brake calipers or wheel cylinders at each wheel.

This hydraulic pressure activates the brakes, allowing them to clamp down on the brake rotors or drums, thereby slowing down or stopping the vehicle. The efficiency of this conversion process is vital for effective braking performance. Understanding this role is essential for diagnosing brake system issues, as any malfunction in the master cylinder can compromise the entire braking system's effectiveness and safety.

The other options relate to different vehicle functions: storing brake fluid is a minor aspect, controlling wheel alignment pertains to steering and suspension systems, and monitoring tire pressure is part of the vehicle's tire management system. Each of these roles is important but does not pertain to the primary function of the master cylinder in hydraulic brake systems.