Mercedes-Benz SLK350 Brake fluid is black or brown Inspection at your home or office.

Common reasons for this to happen:

• Normal Aging Gone to the Extreme: The most common reason that brake fluid appears brown or black is that normal aging has gone unchecked (you haven’t had the fluid changed in too long). Contaminants collect in the fluid, darkening the color and reducing its ability to work.

• Moisture Contamination: Brake fluid can absorb moisture from the surrounding air. This generally occurs by rubber brake lines allowing moisture to seep in. When moisture accumulates in brake fluid, it causes problems in a couple of ways. Water has a much lower boiling point than brake fluid, and can reach very high temperatures at the calipers and drums. This causes the water to flash boil into steam, causing the brake fluid to darken, but also creating air in the lines. This can cause a soft pedal, or even cause you to have to pump the brake pedal to get the system to work properly.

• Deteriorating Rubber Lines: The rubber brake lines on your car will eventually deteriorate and need to be replaced. Brake fluid is also corrosive, and while the lines are designed to withstand that corrosion, they’ll eventually begin to break down. Microscopic pieces of rubber and chemicals leaching out of the lines into the fluid will also cause it to darken.

• Normal Heating: Brake fluid is heated by contact with the calipers, and this heat creates a chemical change in the fluid, adding to the darkening created by moisture and other types of contamination.