How does brake fluid get contaminated?
For the most part, the braking system in a vehicle is closed, which means that sand and dirt particles cannot get in through any openings or passages. In theory, this should mean that the brake fluid inside the system never becomes contaminated, and things like flushing or changing the brake fluid should be reserved for the rare occasions when something serious is wrong. Unfortunately your brake system is not theoretically working and moisture can get into the brake fluid through the hydraulic lines. Because this moisture causes the fluid to chemically break down and the moisture begins to rust on the metal components of the system as a whole, you can end up with contaminated brake fluid.
If your vehicle has dirty brake fluid, a brake flush or thorough cleaning is required before changing the fluid to fresh, uncontaminated brake fluid to remove all unwanted particles and residual moisture. The problem is knowing when you have contaminated brake fluid. This is why many mechanics and manufacturers recommend a brake fluid flush every two years or 24,000 miles as a precaution. However, there are circumstances when you should consider flushing your brakes more frequently or you may need it immediately, including:
Driving under hard braking conditions: If, for example, you often tow a trailer or drive in the mountains, you probably need more braking. With such increased demands, moisture enters the brake fluid and begins to break it down faster than usual.
For any other work on the brake system: There are two reasons why a brake fluid flush should be included when changing brake pads or doing other brake maintenance. First, it's easier to do this when you or the mechanic are already there. Secondly, your brake fluid is more vulnerable to the accumulation of moisture and other contaminants when other work is done on that area of your vehicle.
Brake warning lights on the dashboard: When you see the ABS or brake system light on the dashboard, feel free to check your brakes and brake fluid. This often means the fluid level is low, which is likely caused by leaking brake lines, which also allows contaminants to enter the dirty brake fluid.
Noticeable change in pedal pressure: Some people refer to this as a "soft" feel to the brakes, but it actually refers to either the pedal being pushed harder or lighter than normal. Both are bad signs and indicate that you should check the brake system, including checking for contaminated brake fluid, as fluid is likely leaking through the lines or the master cylinder.
Pulls to the side while moving: If your car or truck pulls noticeably to the side while driving, this could indicate a brake fluid leak, which could also mean that the remaining fluid is contaminated with moisture and sand getting in where the fluid exits. Although it may be caused by other problems, it is important to rule out any problems with the braking system for safety reasons.
Contaminated brake fluid can be disastrous, so any brake system problem should not be taken lightly. If you suspect you have dirty brake fluid and may need a brake flush, feel free to call one of our highly trained professionals for advice.
