Skip the auto shop - Our mechanics make house calls

Q: How does brake fluid get dirty?

asked by on

How does brake fluid get dirty?

A: One way that brake fluid becomes contaminat...

One way that brake fluid becomes contaminated is when moisture is absorbed by the brake fluid through rubber brake lines. This moisture will break down the brake fluid and cause rust in the brake system. Excess moisture in brake fluid will increase its temperature because the boiling point of water is lower than that of brake fluid. When this happens air gets into the brake lines and the brakes may become less effective. Brake fluid that has been contaminated by water or moisture can also weaken the master cylinder and caliper rubber seals and lead to brake leaks and an overall failure of the brake system. This type of contamination most commonly occurs in an environment that is particularly humid and in conditions of heavy braking. Another way that brake fluid becomes contaminated is when grime and debris from the brake system accumulates in the brake fluid. Over time, the heat that is generated from braking causes the brake fluid to break down and become contaminated. Brake fluid should normally be changed every two years but this is something that may already be included in the maintenance schedule for your vehicle. Pay close attention to the color of your brake fluid. Normal brake fluid should be a light yellow color and look almost clear, while contaminated brake fluid looks dark brown or black in color.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Front brakes drag

In order to locate the possible cause of your front brakes dragging, you will need to do some tests to isolate the cause. When you are testing the system brakes dragging the lift and support, check both front wheels to...

Q: Slave cylinder leaking

The hydraulic system used on your Honda is the same as your brake system. If there are leaks in the system and air in the lines, the pressure plate cannot be engaged or disengaged which is required to operate the...

Q: Transmission fluid is leaking

I would not recommend driving your truck under these conditions to prevent transmission damage. My first recommendation would be to have your transmission system inspected by an automotive service professional to locate the source of the leak. Possible leak sources...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...