A Guide to the Best Brake Fluid

Have you ever been driving and had that “brake” warning light come on? If so, you know how heart-stopping that little light can be!

When this happens, you pull over immediately and give your brakes a little test, right?

They feel OK. At least I hope they do.

But are they? A quick look under the hood tells you that you are low on brake fluids. You find half a can of brake fluid in the trunk but who knows how old it is. Does brake fluid ever get old?

Maybe you decide to drive to your local automotive parts store and get a new can. That’s great but have you ever looked in an automotive shop and seen all the different numbers and brands?

Which are the best brake fluids to use?

The Best Overall
Motul RBF 600 Synthetic Racing Brake Fluid

For those who do a little street racing or for high-performance cars, of all brake fluids, this is the one to buy.

Don’t confuse this with DOT5 synthetic brake fluid. While the label does say “synthetic”, it also says non-silicone based, which still makes it a DOT4.

Synthetic brake fluid, such as this one, will need to be flushed from the system more often (about every 6 months). It needs to be flushed more often because since synthetic brake fluid absorb moisture.

Some important advice: Do not mix synthetic brake fluid with non-synthetic DOT4 brake fluid.

Only when you are flushing the braking system can you refill with this brake fluid.

This is for those who have hot rods, enjoy riding on the local racetracks, and expect the most from their vehicles. You will be very happy with the performance that this brake fluid gives you. It has great thermal resistance and a high boiling point of 328C.

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The Everyday Budget Choice
Castrol Dot 4 Brake Fluid

Chances are that you know the Castrol name. Perhaps you even buy their motor oil or oil filters. When you see that they also make brake fluid, you will be very happy to buy a brand name you know and trust.

This product works perfectly if your ride uses DOT3 or DOT4 and you are looking for brake fluid to top off your master cylinder. It’s also a great option to keep as a spare bottle around for whenever the need arises.

This is a premium brake fluid, which means that it will exceed the DOT4 specifications. Don’t let the low price fool you, for everyday use or topping up the system, this is a terrific choice.

The Castrol name is one you can trust, so keeping two or three of these on hand is always a good idea.

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The Best Runner Up
Johnsen’s Premium DOT-3 Brake Fluid

Most of us use our vehicles for commuting, family vacations, grocery shopping, and everyday chores.

Johnsen’s DOT3 brake fluid meets and exceeds all DOT3 federal specifications. You can mix it with all other types and brands of DOT3 brake fluid. That means it has a minimum boiling point of 450 degrees.

Check your owner’s manual and see if your vehicle uses DOT3 brake fluid. If so, this is a reliable brand name that you can count on.

One of the things I like about Johnsen’s brake fluid is that it comes in a big one-gallon size. This means that when I need to flush the brake system, I don’t have to open 3 or 4 little cans!

If your family has several vehicles, you will want to keep this product in the garage. It’ll be available when you need to check or replace fluids.

Yes, this product is less expensive than the leading brand. But it still does the job without issue or problems of any kind.

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The Best Brake Fluid For Motorcycles
Bel-Ray DOT 4 Brake Fluid

I know how much all you motorcycle fans love feeling the road pass by underneath those two wheels. It’s about as close to flying as you can get while remaining on the ground.

As much fun as “flying” down the road is, stopping is equally important.

If you aren’t sure which brake fluid is best for your motorcycle, try the Bel-Ray Super Dot4 brake fluid. This one is designed with motorcycles in mind. It greatly reduces your chance of vapor lock, brake fade, and brake failure.

Bel-Ray products are well known for their high level of quality. This brake fluid is no exception. There’s a reason they call it SUPER DOT4, right?

This mixes with all other DOT3 or DOT4 brake fluid brands while exceeding all federal laws for brake fluid. Use Bel-Ray Super DOT4 not only for your brakes but the clutch system as well, if applicable.

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Best Brake Fluid For Clutches
Bosch ESI6-32N Brake Fluid

Do you have a standard transmission that uses a clutch? Does it have a slave master cylinder rather than a cable to engage and disengage the clutch? If so, did you know you can use brake fluid to keep the master cylinder full?

There is no special “clutch” fluid used in manual transmissions. They use brake fluid, so don’t fall for the old “muffler bearing and clutch fluid” scam.

How do you know you need to change the fluid? If you are having trouble shifting gears or if the clutch grinds when you try to put it into gear. Check the level of hydraulic fluid in the clutch master cylinder.

If you find that you need to add some to the system, Bosch brake fluid replacement is an exceptional choice. This is a highly compatible fluid that works with DOT3, DOT4. Or DOT5.1.

This exceeds the federal standards for hydraulic fluid. It only needs to be replaced every 3 years, rather than every 2 years, like many types of brake fluid.

Bosch is a huge brand name in automotive replacement parts. It is one of the industry’s leaders in modern braking systems so you know you can rely on this product to get the job done.

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What Is The Best Brake Fluid For A BMW?
ATE Original TYP 200 Racing Quality DOT 4 Brake Fluid

Let’s face it, most BMW owners love to do some racing in their cars, especially those Z owners. You want a brake fluid that is going to stand up to the heat generated when you apply the brakes.

ATE Original TYP 200 brake fluid is the perfect choice for your BMW. It has non-foaming agents and a minimal decrease in the actual boiling point of the fluid.

It also has a special mix of compounds that minimizes water absorption. This is a DOT4 brake fluid, so you can use it in your BMW as long as the manufacturer doesn’t call for a DOT5.1.

I like this brake fluid for BMW’s because you only need to do a brake line flush and replacement every 3 years. That saves a considerable amount of cash compared to every other year.

It’s true that you can use any brand of DOT4 brake fluid. Especially if you only use your Bimmer for regular around town or “doing the speed limit” type of driving.

But for those of you who like to launch their ride for all its worth, the ATE Racing brake fluid is something you should consider buying and using.

This one is for those BMW owners who enjoy pushing their car to the max on the track. Even if you just do a few high- speed runs on the freeway regularly, this high-performance racing brake fluid is the one you need. Because nothing but the best will do. 

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What Is The Best Brake Fluid For A Honda?
Genuine Honda DOT 3 Brake Fluid

If you own a Honda, I bet you baby your car like it’s, well, your baby. I worked for Honda for many years, so I know full well how much Honda owners love their cars.

If you are looking for the perfect brake fluid for your ride, you will want to use Genuine Honda Brake Fluid. This is made by Honda and if your owner’s manual calls for DOT3, this is the one for you. Do not use this for models using DOT4 or DOT5.1.

Honda makes all their genuine fluid and other parts to their exact specifications for a reason. It’s the best for your Honda! Why use anything that may not meet Honda’s stringent specifications?

Be careful not to let this brake fluid drip on the paint or plastic parts!

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What Is Brake Fluid?

Brake Rotor

Brake fluid is a hydraulic fluid that transfers the force you put on the brake pedal into amplified pressure. This pressure operates the wheel cylinders and pistons to slow the vehicle.

Most brake fluids are either glycol-ether or synthetic glycol. DOT5.0 is a silicone-based brake fluid that cannot be mixed with other types of brake fluid.

Does Brake Fluid Go Bad?

If that open can of brake fluid in the trunk or garage is more than a year old, ditch it.

If you aren’t sure about the age, you should probably toss it.

Brake fluid absorbs water from the air. That means it can make the brake lines rust and put water in the system when what you need is a hydraulic fluid.

My father’s trick was to write the date on the can, so he knew when to throw it out.

What is the Difference Between DOT3 and DOT4?

DOT stand for the Department of Transportation. The main difference between DOT3 and DOT4 is the boiling point of the fluid.

Most people never come close to reaching the maximum boiling point in their everyday commutes or grocery store runs. But it can happen on mountainous roads. This is why you must use the correct type of fluid that the manufacturer dictates.

Brake fluid is also prone to water absorption. Both DOT4 and DOT3 will absorb water. This is why you should discard any brake fluid that is in an opened container after one year.

If the container is still sealed by the manufacturer, it is safe to use. But you should throw out that old can of brake fluid that has been sitting in your garage for a few years.

DOT3 is more likely to absorb water than DOT4. You can always go up a number but should only use a lower number brake fluid in an emergency.

For example, if your car normally uses DOT3, it is fine to use DOT4 or even DOT5.1. But if your car calls for DOT5.1 and the only brake fluid available is DOT4, you can use it. But you should have the brake system flushed and the proper brake fluid replaced as soon as possible.

Does it Matter Which Brand of Brake Fluid I Use?

Not really.

Like motor oil and gasoline, everyone has their favorite brands. Some brands offer special additives which offer a higher boiling point. They contain anti-foaming ingredients, or they are less prone to absorb water.

It is far more important that you use the correct DOT number for your car or use a higher number. Most vehicles have this information in their owner’s manual. Some have the minimum DOT number listed directly on the brake master cylinder reservoir cap.

If all else fails, you can google it. You will be sure to find this information about your exact year and model. You can also ask your local mechanic or call the dealership.

How Do I Choose Brake Fluid?

You may have heard old-timers say, “Brake fluid is brake fluid is brake fluid.” I know I’ve heard my dad say this, but this isn’t 100 percent true. When you hear this, they’re mainly referring to brands.

First, you need to know what type of brake fluid your vehicle uses. Each can of brake fluid has a number on it, such as DOT3 or DOT4.

Hopefully, you have your owner’s manual, or your cell phone and you can quickly determine which one your car uses.

On occasion, the cap to the brake master cylinder will tell you which type of brake fluid to use.

If you can’t find this information, don’t sweat it. The DOT3 brake fluid or DOT4 brake fluid is simply referring to the boiling point.

You will most likely never get anywhere close to the boiling point in everyday use. You may on certain types of roads. It’s important to find out and use the manufacturer’s requirement for your car.

For many years, there really was only one type of brake fluid. But cars have changed so much over the years that there are now brake fluids reading DOT4 and even DOT5 and DOT5.1.

What You Need to Know about Brake Fluid

There are 4 different types of brake fluid, each one with a different boiling point, and only one (currently) that is vastly different.

These four brake fluid types are:

  • DOT3
  • DOT4
  • DOT5
  • DOT5.1

That 5.1 number is very confusing. Many mechanics wish that the DOT had chosen another number. But it’s there and we must get used to it.

The main difference between all these numbers is the boiling point and all the numbers.

Except for 5.0 which are either a glycol based type of fluid. They can also be a synthetic version of a glycol based fluid.

DOT5, sometimes called DOT5.0 is a silicone-based fluid. It cannot be used or mixed with any other type. You can not use a different type if your vehicle says it needs DOT5.

Some manufacturers change the color to purple to prevent people from using DOT5 in cars that are not designed for it.

All other types, including DOT3, DOT4, and DOT5.1, should be a clear color or a light amber color. Similar to the color of clean motor oil.

If your vehicle has purple fluid in the brake master cylinder, you CANNOT use anything else but DOT5.

Likewise, if your vehicle has a clear or amber-colored fluid, DO NOT use a purple fluid.

You can use DOT4 in a car that uses DOT3, but only in an emergency should you use DOT3 in a car that has or uses DOT4.

Some Quick Facts about Brake Fluid

You don’t need to be a chemist to pick the best brake fluid for your car. All you need is a few facts.

  • You can mix brands.
    • Some people might tell you that you should never mix brands, but this isn’t true. It’s the DOT number that is most important. As long as you aren’t adding DOT5 when your car doesn’t have that already, you will be fine for a short time. If you mix Lucas DOT4.0 brake fluid with your Wagner DOT4.0 brake fluid, it’s OK.
  • Is it OK to mix DOT3 and DOT4 Brake fluid?
    • Even if you mess up and add the wrong type of fluid, you will be OK. Remember that as each number goes higher, the boiling point of the brake fluid goes up as well. So, if your vehicle has DOT4 in it right now and you accidentally add DOT3, it’s fine. This will mean that the brake fluid is now working at a DOT3 boiling point.
  • What happens if I use the wrong brake fluid?
    • If you later discover that you should have used DOT4, you can always get the brake system flushed and have the correct fluid added. I believe that driving with a bit of DOT3 brake fluid, rather than DOT4, is far better than being low on brake fluid.
  • Why is the brake fluid I bought purple and the stuff in my car is amber?
    • This is about the only mistake that matters. DOT5 brake fluid is made purple and all other DOT numbers are clear-ish or amber-colored. These two should not be mixed. DOT5 brake fluid is synthetic, the others are not. If you see purple brake fluid in your car, buy DOT5. If your vehicle has amber-colored brake fluid, buy DOT5.1, DOT4, or DOT3.

How To Change Brake Fluid

In Conclusion

As simple as brake fluid is, the different numbers, colors, and use-by dates can be confusing. Especially if you only top off your vehicle one every three years or so.

Some find it easier to make a small tag and put it on the glove box door with the correct brake fluid type. Others like to mark the container of brake fluid with the date they purchased it. Just make sure you discard it after about a year!

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Jason Caldwell

Jason Caldwell

Car Fanatic. Performance Geek. Flathead lover.

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