What Color is Brake Fluid? (Differences & When to Change)

When you hit the brake pedal, you expect your vehicle to stop. And brake fluid is one of the important components that go into this critical action; without it, you’re in trouble.

But brake fluid is also a topic that often leads to confusion. Therefore, no matter if your vehicle is low on brake fluid, leaking, or if it’s time to do a brake fluid flush, it’s a good idea to have some basic knowledge about it.

So, what color is brake fluid? And how do you know when it’s too old and when to change it? Well, to answer these questions, you’ll also need to know a little more about the differences between brake fluids. Luckily, we got all the answers here!

Differences Between Brake Fluids

Before diving into what color brake fluid is and when to change it, we want to quickly give you a walk-through of the different types of brake fluid.

There are mainly four different brake fluids which can be divided into two types; glycol-based and silicone-based. The glycol-based brake fluid includes DOT 3, DOT 4, and DOT 5.1, which are all the same color. Then there’s DOT 5, a purple, silicone-based brake fluid.

The main difference between glycol- and silicone-based brake fluids, and why you can’t mix them, is that the glycol-based brake fluid absorbs moisture, while silicone-based is hydrophobic, which means it doesn’t.

When a vehicle is frequently used, a small amount of moisture isn’t usually a problem. But under certain circumstances, such as those vehicles that sit for long periods, DOT 5 may be a better option since moisture seeping into the system can cause corrosion and freezing. That’s why it’s commonly used in collector cars and military vehicles.

Due to their way of handling water, do NOT combine glycol and silicone-based brake fluids. Only add DOT 5 brake fluid to a completely dry system or a vehicle that already has DOT 5 in it. Nothing other than DOT 5 should be added to a system requiring DOT 5 brake fluid.

So, now that you know a little more about the different types of brake fluid, you are probably wondering what the most common brake fluid is.

Well, the most common brake fluids used in most vehicles are the glycol-based, DOT 3, DOT 4, and DOT 5.1. They are all the same color and compatible with each other. The difference between these brake fluids is primary their wet- and dry boiling points, viscosity, and corrosion prevention.

DOT 3 and DOT 4 are standard fluids, suitable for anything that doesn’t specify anything else, and DOT 5.1 is usually used in high-performance or heavy-duty vehicles.

To know what brake fluid to use in your vehicle, see the master cylinder cap or car owner’s manual, or ask a mechanic technician to help you. 

What Color is Brake Fluid

The color of brake fluid in good condition should be nearly clear or yellow tinted. However, brake fluid will naturally darken over time as it slowly becomes contaminated as the brake fluid gets older and gradually absorbs moisture. If the brake fluid turns black or dark brown, it’s too old and needs a change.

The same goes for the silicone-based DOT 5 brake fluid. As discussed above, this purple brake fluid doesn’t absorb moisture. But, as it gets older, it will darken due to exposure to heat and contamination of dust and wear particles.

Whether you’re changing the brake fluid as part of your car’s routine maintenance or topping it off after a rotor and brake pads replacement, it is important to know the color of healthy brake fluid to make sure your car’s braking system is in tip-top shape and working as it should.

How Do You Know if Brake Fluid is too Old and Bad?

As discussed above, brake fluid will darken as it gets older and more contaminated. And you’ll know the fluid is becoming too old when the brake fluid begins to turn black or dark brown.

Contaminated brake fluid can cause a number of problems, including increased wear on brake components, corrosion, reduced braking performance, and even complete failure of the braking system.

Failing to keep the brake fluid oil clean is the main cause of these problems. So, it’s important to check your brake fluid level regularly and that it’s clean and yellow tinted, or amber color to ensure that your brakes will always be there when you need them.

How Often to Change Brake Fluid

You don’t think about brake fluid very often, do you? Neither do I. The truth is, brake fluid is easily forgotten when doing the routine maintenance of your car. However, as it inevitably gets older and contaminated, the color of the brake fluid should never get to the point where it has turned black or dark brown.

Most experienced mechanics and manufacturers recommends brake fluid should be changed regularly, and the best way to find out how often you should change brake fluid is to follow the recommendations of your vehicle’s owner manual.

Some manufacturers recommend changing the brake fluid every 25,000 miles or two years, while others may say you should change it every 45,000 miles or three years.

And there is even some make and models such as Ford Escape, Hyundai Elantra, and Toyota Camry that doesn’t even have any recommendations for when to change brake fluid, only instructions to inspect it regularly.

As a rule of thumb, most mechanics will recommend changing the brake fluid every 45,000 miles or three years – whichever comes first.

Here are a few other signs that you need to change brake fluid.

  • The brakes feel spongy, bouncy, or soft when you press the pedal.
  • Your vehicle’s anti-lock braking system (ABS) dashboard light is on.
  • Your vehicle’s braking performance is reduced.
  • There’s a burning smell from overheated brakes.

Some of these are also symptoms for other brakes-related problems such as bad rotors. So, if you notice any of these signs, it’s a good idea to have your vehicle’s brakes checked by a qualified mechanic as soon as possible.

How to Change Brake Fluid

how to change brake fluid

Changing brake fluid- or doing a brake fluid flush, as it is also called, is an easy task. But, before anything, you need to make sure to read and fully understand how to bleed the brake system properly.

A brake bleed can be done by yourself, which is a little bit more tricky, or by doing a 2-person brake bleed. However, if you are unsure how, always take your car to your preferred mechanic and ask for the fluid to be flushed.

Here’s a step-by-step guide on how to change brake fluid:

1. PLACE YOUR CAR ON JACK STANDS

Park your vehicle on a flat surface. Open the hood, jack up your car, place it on jack stands, and remove the wheels.

2. REMOVE THE OLD BRAKE FLUID

Locate the master cylinder and uncap it. Use a turkey baster, vacuum pump, or syringe to remove most of the old brake fluid, but don’t completely dry it.

3. ADD NEW BRAKE FLUID

Add new brake fluid to the master cylinder, and keep the cap off or loose to allow airflow. NOTE: Make sure you use the right brake fluid for your vehicle; it should be marked on the master cylinder cap. Otherwise, consult the car owner’s manual. Don’t forget to put the cap back on the new brake fluid bottle.

4. BLEED IN CORRECT ORDER

Now it’s time to determine what wheel to bleed and the correct order. For most cars, you usually start with the wheel at the corner furthest from the master cylinder. If you are unsure, then check your instruction manual.

5. LOCATE THE BLEEDER VALVE/NIPPLE

Locate the bleeder valve/nipple, also called bleeder screw. Look for a small screw with a hole in the middle. It’s usually located on the top of the brake caliper on disc brakes or at the top middle on the backside of the brakes on drum brakes. Spray each with brake clean to clean off old grease and connect a tube.

6. PUMP 3 TIMES THEN HOLD

Having a second person to help you is now a good idea. Tell the helper to jump into the driver’s seat, carefully pump the brake pedal three times, and then hold it down with pressure. Use a command like “PUSH” or “HOLD” to signal.

DO NOT PUSH THE BRAKE PEDAL TO THE BOTTOM WHILE PUMPING OR HOLDING PRESSURE.

7. LOOSEN THE BLEEDER VALVE

While the helper is still holding pressure, you loosen the bleeder valve with a brake wrench fitting the bolt. You should now see fluid and likely bubbles coming out. The brake pedal should still be pushed down and not moving.

8. CLOSE THE BLEEDER VALVE

When no more fluid or bubbles is coming out, close the bleeder valve and use a command like “RELEASE” to signal the second person to release pressure from the brake pedal. Make sure the master cylinder doesn’t bleed dry. Continue to add new brake fluid if necessary.

9. REPEAT STEP 6, 7 AND 8

Now repeat the steps. Pump the pedal three times, push it down and hold pressure, open the bleeder valve, wait for the fluid to stop, and close it. Keep doing this until you stop seeing bubbles and the color of the brake fluid is the same as the new. Dispose of the old brake fluid in a plastic reservoir.

10. REPEAT ON THE OTHER THREE WHEELS

Close the brake bleeder and release the brake pedal. Now remove the tube and repeat on the other three wheels.

11. FILL UP THE MASTER CYLINDER

When you’re done, fill the master cylinder to the “max” or “full” line, and don’t forget to close up the cap. When now applying pressure on the brake pedal, it should feel firm.

12. PUT WHEELS BACK ON YOUR VEHICLE

Put the wheels back on; it’s time to go for a test drive to ensure the brakes are working properly.

That’s it! You’ve successfully changed your brake fluid, and now you know exactly how to bleed your brakes next time.

Tips For Caring For Your Vehicle’s Brakes

With this article, we also wanted to highlight a few things you can do to keep them in good condition, so you can expect them to stop your vehicle when pressing the brake pedal. But also to ensure the longevity of the brake system because, in the end, TLC for your car is more important than you think.

  1. Check brakes and brake pads regularly.
  2. Check brake fluid regularly.
  3. Listen and look for warning signs.
  4. Keep distance and use “engine brake” to slow down before applying brakes.
  5. Follow the routine maintenance.

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