Why Is My Brake Fluid Black? [Reasons & Solutions As Well As Flushing Guide]

Our vehicle needs several fluids for continuously operated. For example, engine oil, transmission fluid, brake fluid, and so on. You will also discover different colors of brake fluid, which provide different signs of fluid. To check out the color of the fluids, you will easily say that the brake fluid has good or bad conditions.

So, why is my brake fluid black? If your brake fluid looks black color that means the fluid is contaminated heavily. When the fluid becomes older, the brake fluid probably turns black. Black fluid first affects the brake system. Besides, black brake fluid means your vehicle rubber gasket has deteriorated, and of course, the liquid of the tank is too old, and you should replace it as soon as possible.

But why is your brake fluid contaminated? Is it safe to drive when your vehicle brake fluid becomes black? Or what is the solution? Don’t worry; from this article, you will get a complete solution as well as a clear concept.

Why Is My Brake Fluid Black

Why Is My Brake Fluid Black?

When you open the brake fluid reservoir, you notice the black color fluid. But why the brake fluid turns black? There have been some causes worked here. Let’s find them step by step.

First, the main cause is contamination. When the brake fluid comes with heavy contamination, the brake fluid becomes black and unable to reduce pressure.

Second, so many drivers strongly believe that brake fluid turns black because of age. When it becomes too old, the fluid will degrade. In this situation, you have to replace the fluid as soon as possible.

Third, the other visible reasons I found to turn the brake fluid black are the gasket on the auxiliary cylinder, rubber brake lines, wheels, fluid tank, and so on. These problems come out because brake fluid is corrosive.

Fourth, the parts of the engines are corrosion, tear, and wear, which are other reasons to affect the brake fluid. Overall, these are the common causes you find due to brake fluid turning black.

Why Is the Brake Fluid Easily Contaminated?

There are plenty of reasons have which brake fluid is easily contaminated. Though the brake fluid system has a proper seal, the steam can easily pass through the microfiber, rubber hose, ring, and others.

However, I am going to disclose some core reasons which contaminated your vehicle brake fluid easily. So, let’s break down the list and be aware of the facts to protect your vehicle brake fluid.

  • Don’t change the brake fluid from time to time
  • Effects of excess humid weather
  • Rust and corrosion of the brake or brake’s parts
  • Don’t use quality brake fluid

These are the core reasons. On the other hand, the driving system, brakes, pedal, and other things also help the fluid easily contaminated.

Brake Fluid Discolored

Good brake fluid always plays an important role in the brake system. When you continuously use the fluid, the fluid turns into different colors to provide different signs.

First of all, black color brake fluid means the fluid is highly contaminated, and you need to replace the fluid as soon as possible. On the contrary, black fluid directly affects your vehicle brake system and reduces the pressure.

Secondly, muddy or brown color is another bad sign of the fluid. When the fluid becomes older, you will find out the fluid is muddy or brown, which you need to replace.

It would be better for you to show the oil condition of an automobile expert to solve the problem. On the other hand, you will also take help from automobile shops.

How to Flush Black Brake Fluid?

A vehicle owner should flush the brake fluid once a year. But, it is also a good idea to flush the brake fluid after 6 months. However, if the fluid already comes with black color, you should flush the fluid immediately.

Before starting the step-by-step guideline, you should wear safety glasses and other equipment. So, let’s get started with the step-by-step guideline.

Step 1: Prepare the Car

In this step, you need to set the car in gear, and of course, you need to place a thing behind the wheel so that the car doesn’t move.

Step 2: Find out Master Cylinder

Open the hood of your vehicle and find out the master cylinder. This is the beginning place where the fluid-filled from. You need to open the cylinder cap and place an old rag.

Step 3: Remove All Fluid

After opening the cap, you need to suck out all of the old fluid. Probably, you will remove 20% to 30% of the fluid, which is enough.

Step 4: Refill the Fresh Fluid

Now, it is time to refill the fresh fluid. Make sure that you are using quality brake fluid for your vehicle.

Step 5: Start Brake Caliper

In this step, you need to find your car’s brake caliper. First of all, you can check out the manufacturer’s order, and secondly, check out the driver seat areas to find out the brake caliper. If you find out the caliper on the driver’s side, you need to start the driver seat brake caliper first.

Step 6: Remove the Wheel

After securing the car by using jack stands, you need to remove the wheel. Take your time to remove the wheel carefully.

Step 7: Find Out Bleeder Valve

Locate the bleeder valve. It helps you attach with a rubber hose so the fluid doesn’t drip everywhere.

Step 8: Pump the Brakes

Hire an assistant to pump the brake for 3 to 5 minutes continuously, and of course, he should notice that it gets stiffer. He needs to do it until the fresh fluid come out continuously.

These 8 steps allow you to flush your vehicle’s black fluid easily. The guideline is simple and effective to complete. If you think the process is complicated, you will take flushing service from a reliable automobile shop.

Brake Fluid Black after Flush

After flushing the black fluid, it should come out of the fresh fluid. If you still face your brake fluid black after flushing, probably, you failed to flush the fluid properly.

Sometimes, pumping the brake does not come in the correct way. You should be continuously pumping until the fresh brake fluid comes out.

On the other hand, you should also check out your brake fluid quality. The brake fluid should come with high quality so you can get the service for a long-time.

Can You Drive When Brake Fluid Is Black?

Black color fluid is not a good sign for your brake fluid. When you find black fluid on your vehicle, it means the fluid is contaminated with moisture and other elements.

Is driving a good option when my car brake fluid is black? Experts never suggest driving when the brake fluid becomes black. When you drive your car with black brake fluid, the brake system probably comes with great issues.

Black fluid produces a large amount of foam and gas when you are continuously driving. So, it is advisable for you to avoid driving when your vehicle brake fluid is black.

FAQs (Frequently Ask Questions)

Q: What color should brake fluid be?

Answer: The fresh brake fluid color almost comes with yellow color. The brake fluid color should not come with pure gold color. On the other hand, if you find the fluid color brown/black/mud, you need to replace the fluid as soon as possible.

Q: Why is my brake fluid dirty?

Answer: Moisture and unwanted particles are the main reasons for dirtying the brake fluid. On the other hand, wearing a fluid filter is another cause that also makes the brake fluid dirty. There are plenty of reasons I found which make the fluid dirty.

Q: Does brake fluid absorb water?

Answer: The official answer is yes. Brake fluid absorbs water because brake fluid is hygroscopic. It is not only absorbed water but also absorbs moisture.

Is It Clear to You?

Brake fluid is an inseparable part of the vehicle. To see the color of the fluid, you can easily tell the condition of the oil. However, black brake fluid color means heavily contaminated fluid or old fluid. This fluid is not a good option for your vehicle. So, if you find black fluid in your vehicle, you should replace it as soon as possible.

Read Also: When To Change Brake Fluid? Importance Of Maintenance


Emon is Lubricants specialist who studied on Petroleum Engineering in UAE. He have more than 10 years experience on different kinds of lubrication including automobile troubleshooting.