Can your brake fluid take it?

Posted on June 28th, 2016 by Rob Marshall


While many people know that a low, or empty, brake fluid reservoir will result in considerably reduced braking (or possibly, compete failure), many drivers are unaware that old brake fluid poses a specific danger in the summer.

As the braking system performs the physical function of transforming motion into heat, the brake fluid has to remain stable as its temperature increases. While brake fluid is designed with a high boiling point (typically, an average of 250 degrees Celsius), the types used for modern cars absorb moisture from the atmosphere and the increased water content within the fluid decreases the boiling point.

Should the brake fluid boil in use, the brake pedal will sink gradually to the floor and stopping distances will increase, or the car might not stop at all. Naturally, warmer summer weather (as well as towing and negotiating steep descents) increases the risk markedly. The higher water content also promotes corrosion within the braking system.

If you are faced with a forthcoming long drive to a holiday destination, drop in to your local garage and ask for the brake fluid’s boiling point to be checked. If the fluid has not been changed for at least two years, book the car in for a fluid flush.