When should brake fluid be replaced?

Replacing brake fluid is essential for maintaining an effective braking system, as it can degrade over time due to moisture absorption and contaminants. The correct response highlights two key aspects: the visual condition of the brake fluid and adherence to the vehicle's service manual recommendations.

Brake fluid should be replaced if it looks dirty, which indicates that it has absorbed moisture or has become contaminated with debris. This contamination can decrease the fluid's boiling point, which is critical for safe braking performance and increases the risk of brake failure. Additionally, following the service manual's recommendations ensures that the replacement schedule aligns with the manufacturer's guidelines, which are based on testing and engineering assessments.

In contrast, suggesting a monthly replacement disregards the actual condition of the fluid, as some vehicles may not require such frequent changes. Replacing brake fluid only during brake pad replacement ignores the potential need for fluid replacement due to contamination or degradation. Lastly, waiting until the brakes feel spongy may indicate that the fluid has already compromised braking effectiveness, thus delaying necessary maintenance can lead to unsafe driving conditions.