When stepping onto the brakes of our cars, the brake fluid is responsible for transmitting the pressure applied to the pedal to the brake pads, which will then slow down the vehicle. Utilising the principles of hydraulics, brakes are precise, yet powerful components of our cars.
The medium used in modern disc brake braking systems is subject to a number of requirements. For example, the braking needs to be consistent, i.e. whenever we step onto the brake with the same strength, the braking should be the same. This is to allow the driver to apply the braking force needed in any particular situation. This needs to be predictable in order to safely operate the car.
Further, the brake fluid needs to withstand heat as the pressure within the system will generate heat when braking. The fluid needs to be stable and requires thus a higher boiling point than water for instance. Brake fluid, despite all its good characteristics, is however hygroscopic, meaning it attracts water. This is of particular concern in tropical countries with high humidity, as our colleagues at German Motors will know.
Over time, the brake fluid not only attracts water, but it is also deteriorating as it ages. Pollutants may enter the system, thus further reducing the effectiveness of the liquid. One will notice that the braking is becoming spongy, and the brake pedal may even become loose and bouncy. These are important signs that the brake fluid is due for a change.
Brake fluid should be changed regularly, as per the instructions of the car’s manufacturer. As seen, the brake fluid is aging, attracts water over time; as a safety concern, changing brake fluid does not take long or cost a lot of money. Changing brake fluid should be done carefully: brake fluid is highly corrosive and should not get in contact with skin. When spilled, it may also damage engine parts. Special tools to facilitate the brake fluid change are available and their use is recommended.
Time and mileage are the usual determinants of when the brake fluid should be changed. However, outside the regular interval, a change may also be required, should the brake fluid have deteriorated faster than anticipated. A visual inspection may hint at the need to change it. Over time, brake fluid will become cloudy and dark. A special tool can measure the boiling point of the fluid and if it has fallen below a safe boiling point, the brake fluid should be replaced. It should also be replaced with brake fluid in the correct specifications.
Next time when you are at German Motors, ask for a quick demonstration of how to spot the brake fluid reservoir to gauge yourself if there could be a need to replace the fluid.
