We’ve previously talked a lot about how brake pads, brake clips, and rotors affect driving performance and noise. However, there’s another important aspect to your braking system that often gets overlooked, changing BRAKE FLUID.
Brake Fluid Basics
Without brake fluid, your car wouldn’t stop because it transfers the force you create when you step on the brake pedal onto the hub of the wheel. Brake fluid also lubricates movable parts within the brake system and prevents corrosion.
Brake fluid is a “hydraulic fluid” which moves the components in your vehicle’s braking system. There are four types of brake fluid sold; all are regulated by the Department of Transportation (DOT).
“Most drivers should be changing brake fluid every one to two years.”
Each variety has it’s own boiling point and the type you use depends on the age, size, and brake system (ABS or traction control) of your car. The best way to ensure you’re using the right one is to to check your owner’s manual.
It’s especially important to check your brake fluid periodically if you live in a mountainous region or tow heavy equipment for extended periods. Since more heat is generated under heavier braking conditions, it’s possible that your brake fluid can exceed its boiling point and form vapor bubbles, which can cause brake failure.
Most “regular drivers” should be changing brake fluid every one to two years, (check your owner’s manual).
If you’re not changing brake fluid when recommended, you risk brake failure due to contamination, which leads to deterioration.
What causes brake fluid to deteriorate?
Even though your brake system is “closed,” meaning bits of dirt can’t make it through any obvious holes, moisture can still penetrate your car through the pipes and hoses. That moisture causes the fluid to deteriorate because the boiling point of brake fluid can be severely reduced when it is ‘wet’ (i.e. contaminated with water) compared to when it is ‘dry’ (i.e. has no water content).
“Moisture makes brake fluid deteriorate.”
Moisture can also rust metal components in the brake system, another way you can wind up with contaminated brake fluid.
Got dirty brake fluid?
If your vehicle has dirty brake fluid, it needs a brake flush or a thorough cleaning to remove any moisture or unwanted particles before replacing the fluid. The problem lies in knowing when you have contaminated brake fluid before the customary two-year, 24,000-mile mark.
Here are a few circumstances that may indicate you may need a brake flush:
Heavy Brake Use.
We’ve already mentioned this, but it’s worth repeating that if your driving habits demand a lot out of your brake system – you frequently tow a trailer or drive through the mountains– moisture can more easily get into your brake fluid and contaminate it more quickly than usual.
Brake Warning Lights.
When your ABS or Brake System light goes on, get your brakes and brake fluid checked ASAP. An illuminated light often means your fluid levels are low, probably due to a leaking brake line, which allows contaminants to enter and pollute the brake fluid.
Noticeable change in pedal pressure.
Contaminated brake fluid is just one of the reasons why the pedal is either harder or easier to depress. You could have a leak through a brake line. You could need new brake pads and hardware. Whatever the reason, fix the problem to be safe.
Pulling to one side.
There are many reasons why your car or truck may be pulling to one side as you drive. If it’s because of a brake fluid leak that would mean the remaining fluid is contaminated.
We cannot stress enough that when there’s any issue with your brake system, it’s very important to get it checked ASAP to ensure your safety and the safety of everyone else on the road.
Changing Brake Fluid Yourself
If you want to save some money, you can do a complete brake flush and bleed yourself. Want an awesome tutorial? This 12-minute video by Chris Fix is a great step-by-step guide that covers all the bases. (Chris has one of the top automotive “how to” video channels on YouTube.)