What is the impact of moisture in brake fluid?

• A. It has no significant effect on the braking system
• B. It reduces the cost of brake fluid
• C. It lowers the boiling point, increasing the risk of brake fade
• D. It enhances the lubrication of brake components

Answer: (C)

Moisture in brake fluid significantly impacts the braking system by lowering the boiling point of the fluid. Brake fluid is designed to operate under high temperatures, and its boiling point is critical to maintaining effective braking performance. When moisture enters the brake fluid, typically through absorption from the air (as brake fluid is hygroscopic), it causes the boiling point to decrease.

This reduction in boiling point can lead to a phenomenon known as brake fade. Brake fade occurs when the brake fluid reaches its boiling point during heavy braking situations, causing vapor pockets to form in the brake lines. Since vapor compresses more easily than liquid, this results in a spongy brake pedal feel and a decrease in braking efficiency. In extreme cases, it may lead to complete brake failure, presenting a serious safety risk.

Thus, moisture in brake fluid not only poses a safety hazard by risking effective braking performance but also emphasizes the importance of regular maintenance and fluid replacement in hydraulic braking systems to ensure reliability and safety.