Water contamination will drastically reduce the boiling point of your BMW's brake fluid and eventually destroy the brake hydraulic components. Once brake fluid begins to boil, the result is brake fade which translates into not stopping your vehicle! A high quality DOT 4 brake fluid has a dry boiling point of 430 degrees. Although it's hard to imagine, under severe brake the brake pad to rotor contact surface will exceed those temperatures. This will occur under severe braking for extended periods of time, such as long down hill grades.
With as little as 3% moisture contamination the brake fluid boiling point may drop to 280 degrees. Depending on the age and brand of brake fluid that was originally installed.
How does water get into the brake fluid?
The moisture comes from the atmosphere. Brake fluid is designed to absorb water rather than have the water form a water pocket in the brake system. Regions with high humidity (like East Texas) will contaminate the brake fluid much faster than the dry deserts of Arizona.
How to tell if your brake fluid need flushing
New brake fluid is typically clear or has a slight yellow tint. Any dark or mud like discoloration is way over due. The dark discoloration will consist of abrasives that will accelerate brake system component wear. Resulting in system leaks and failure. Our technicians each have an electronic test probe that instantly measures the moisture content by simply probing the surface of the fluid.