One thing that is commonly overlooked during a service is brake fluid. Just because the reservoir is full does not mean the brake fluid is ok. All auto manufactures specify to change your brake fluid every 2 years, which may seem excessive for such an unknown fluid, however this little ignored and sometimes hidden reservoir under your hood contains one of the most important fluids, as your life depends on it.
Why do I have to replace my brake fluid? The short answer is:
Brake fluid is Hygroscopic. But what does that even mean?
(hy·gro·scop·ic: adjective - a substance tending to absorb moisture from the air.)
This is a problem since brake fluid is a hydraulic fluid that makes your car stop. As the brake fluid absorbs moisture from the ambient air it will slowly raise the water content of your brake fluid. Generally we see 1% per year of water absorb into brake fluid. This can be higher depending on many different variables including how close you live to the beach, if your car is not kept in a garage, and the weather.
So what happens if I don't change my brake fluid?
A few things happen. all of which are not good:
1. The moisture will corrode or rust the brake hydraulic components and will cause them to fail which results in costly repairs into the thousands, and can cause dangerous brake failure. Common failures due to lack of brake fluid changes are: Seized brake calipers, leaking master cylinder, rusted through brake lines, and damaged ABS unit.
2. As the water content raises the boiling point of brake fluid lowers which will cause brake fade under high heats from excessive braking, mostly experienced in heavy usage of brakes down a large downhill grade, emergency stops, or "spirited driving".
3. Spongy brakes. Once the brake fluid is around 4-5% water you will experience a loss in braking performance under all braking conditions making your brakes feel "spongy" or "squishy".
101 European uses specialized testers to test the water content of your brake fluid to monitor and let you know when its time to change it. We also use the highest quality German brake fluid available in the industry with a higher boiling point to handle more heat associated with more aggressive driving.