Brake fluid is also corrosive, and while the lines are designed to withstand that corrosion, they’ll eventually begin to break down. Deteriorating Rubber Lines: The rubber brake lines on your car will eventually deteriorate and need to be replaced.This can cause a soft pedal, or even cause you to have to pump the brake pedal to get the system to work properly. This causes the water to flash boil into steam, causing the brake fluid to darken, but also creating air in the lines.

Water has a much lower boiling point than brake fluid, and can reach very high temperatures at the calipers and drums. When moisture accumulates in brake fluid, it causes problems in a couple of ways. This generally occurs by rubber brake lines allowing moisture to seep in. Moisture Contamination: Brake fluid can absorb moisture from the surrounding air.Contaminants collect in the fluid, darkening the color and reducing its ability to work. 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).In serious situations, you may have to pump the pedal a couple of times for it to work properly. You may have noticed that your brake pedal feels softer, or spongy. This reduces the system’s ability to build pressure, which compromises your braking performance. Very dark colors indicate that your fluid has collected a significant amount of contamination, and might have absorbed moisture, as well. It’s important that your brake fluid is changed regularly, before it turns brown or black. In severe situations, your brake fluid may appear to be brown, or even black (think used engine oil). It will darken over time, changing from clear/golden to a darker gold. It requires only a couple of years for the fluid to build up enough contaminants that the color begins to change. This happens on all vehicles, even brand new ones. Over time and through normal use, brake fluid becomes contaminated. You have two types of brake lines – steel and rubber. This is true whether your car requires DOT 3, 4 or 5 brake fluid.īrake fluid is held in the master cylinder reservoir, but it is also stored in the brake lines that run from the master cylinder to each wheel. In a normal system, the brake fluid is clear or very light gold in color. The master cylinder and brake booster work to create pressure, which is then directed to the moving parts of the system (the calipers and shoe actuators). Your brakes are operated by fluid pressure.

Dot 3 brake fluid color chart