Is Dark Brake Fluid Bad for Your Car? – DOT Color Breakdown

There is no need to talk about how important brakes are for any car as anyone who has ever interacted with any vehicle would know how important it is to control the speed and stop the car at will.

The braking system is an assembly with multiple cogs and the clean brake fluid plays an integral role in transferring the force from your brake pedal to the tires and forcing the vehicle to stop.

Over time, that black brake fluid might deteriorate or get contaminated, which changes its color to dark brown or black.

Dark brake fluid is a common issue and obviously, as a car owner, you won’t care about your brake fluid changing colors.

The main concern would be its effect on the performance of your vehicle. 

Read on to find out.  

Why Does Brake Fluid Change its Color?

The main reason behind this is time. Brake Fluids are hygroscopic, meaning that they interact with water differently and absorb it.

The increase in water content leads to a significant increase in the overall absorption capabilities of the mixture, leading to it getting contaminated by dirt, dust, and microscopic particles surrounding the air.

Thereby, resulting in the darkened appearance this write-up is focusing on.

How Does Brake Look Like Regularly?

Regular buyers of car fluids know that brake fluids have different specifications determined by the Department of Transportation (DOT).

DOT standards determine 4 types of brake systems and fluids according to their application, suitability, composition, and much more.

The biggest distinguishing factor is their color, and here’s a breakdown of the color grades associated with the brake systems and fluids by DOT:


Commonly used in many vehicles. Can appear in clear, yellow, blue, and red shades.


For drivers who put a lot of pressure on their brakes by accelerating/decelerating. Can appear in light yellow dark brown or crimson shades.


For vintage cars or custom-made applications. This brake fluid color will always have a purple shade.

DOT 5.1

Available in blue, clear, and yellow shades. Special fluid for very high temperatures and performance applications.

The Perils of Dark Braking Fluid

You might ask if it is bad if brake fluid is dark and the answer is yes! The brake fluid color change indicates an issue with the brakes and should be addressed as quickly as possible.

When it comes to car safety, the first thing that’d pop into your mind is the brakes. Obviously, our first instinct is to stop the car in case of an emergency.

However, imagine a scenario where your brakes suddenly start to act up or straightaway give up on you. Sounds bad, doesn’t it?

This is exactly what contaminants in your brake fluid do.

Water, dust particles, and other impurities create pressurized zones in the fluid which prevent the brakes from engaging when they are needed the most and thereby put you in danger.

This phenomenon is called brake fade and it happens when you press your brake where enough, but don’t get any results.

You can’t predict when brake fade occurs, so it’s better to take care of your brake fluid reservoir condition and change it at the first sign of discoloration to prevent any close calls in the future.

Dealing with Bad Brakes: Key Symptoms to Watch for

The first sign of brake fluid failure is the easiest to track. Simply look for discoloration from normal and decide when to change the fluid.

However, it’s also common to overlook it as well. Naturally, who regularly peeks into the hood to check for discolorations?   

Fortunately, you can detect bad brake and fluid pressure while driving as well. There are some key giveaway signs that will tell you that it’s time to look for a change. Here are a few most important ones:

  • Spongy brake pads or pedal: As a driver, you’ll be used to a certain level of sensitivity in your brake pedal. If you notice a sudden change or if your brake pedal feels softer between settings, then it’s probably a brake fluid leak or contamination. Check it out and your car will most probably be good to go.
  • Decreased braking performance: If you notice that your vehicle takes longer to stop or that the brakes feel less responsive, contaminated brake fluid or faulty brake pads will be the culprits.
  • Brake fluid leaks: Check for any visible leaks of other fluids from around the brake system. Leaks in brake system components not only compromise braking performance but also contribute to fluid contamination.
  • Burnt smell: Contaminants bring down the boiling point of the brake fluid and cause it to burn when used. A pungent, burnt odor emanating from the brakes can indicate overheated and contaminated brake fluid.

How Many Miles Should Brake Fuel Last?

Brake fluid is among the few components in a vehicle that won’t deteriorate with time. The fluid will only eventually deteriorate once it starts interacting with moisture.

The brake oil absorbs water and carbon particles so any contaminant can quickly cause issues in the car.

So far, there is no time limit or recommended precaution except keeping your brake oil away from any moisture.

Some people change it every 3 years, but it’s not necessary to waste money.

What’s important is to keep on checking the amount of dirty brake fluid and be on the lookout for the key symptoms of brake fluid contamination discussed above.

Brake Fluid Flush: What is it and How Much Does It Cost?

Brake flush or brake fluid flush is perhaps the most common way of dealing with this issue.

Simply take the car to your mechanic and they’ll replace the existing brake oil with a new one as changing the brake fluid is the only solution to this issue.

Generally, the total costs range from $200 or $250, but ignoring it can potentially put your life in danger.

So, it’s better to go ahead with it whenever you feel your brakes deteriorating and enjoy safe – accident-free journeys.

Key Takeaways

Remember, proper maintenance of the brake fluid is crucial for ensuring the reliability and effectiveness of your vehicle’s braking system.

Regular inspections and following the manufacturer’s recommendations for replacement intervals will help keep your brakes in optimal condition and contribute to reduced braking performance and safer driving.


Dean Alvarez, TireForge Head Author

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