Which component is most directly affected by brake fluid contamination?

The master cylinder seals are most directly affected by brake fluid contamination due to their critical role in maintaining hydraulic pressure within the braking system. Brake fluid is designed to be hygroscopic, meaning it attracts moisture over time, which can lead to various forms of contamination. When contaminants like water, dirt, or particles infiltrate the brake fluid, they can degrade the integrity of the seals within the master cylinder.

Damaged or degraded seals may lead to fluid leaks, resulting in a decrease in braking efficiency or complete brake failure. This compromised seal condition can significantly impact the system's ability to function effectively, as the seals are essential for preventing brake fluid from leaking back into the reservoir and maintaining the necessary pressure for effective braking force.

While other components, such as brake pads, wheel speed sensors, and brake calipers, can suffer from the overall effects of contaminated brake fluid, the master cylinder seals are directly influenced because they are in constant contact with the fluid. Therefore, ensuring the integrity of the brake fluid is vital to maintaining the functionality of the master cylinder and, by extension, the entire braking system.