If you are in a hurry and just want to find out what the best brake fluid is, then we recommend Bosch Brake Fluid as the best one.
If you’re serious about your vehicle maintenance, then you probably put quite a bit of effort into making sure that you’re using the best engine oil and fluids for your vehicle.
But one fluid is easily overlooked by even the most vigilant DIY-enthusiasts, and that is brake fluid. Since the braking system is such a fundamental component for both the performance and overall safety of the vehicle, this is an area that you cannot afford to neglect.
So we created this in-depth review to help you find the best brake fluid for your vehicle, so that you can feel safer knowing that such a critical module is receiving the attention it requires.
Here are the best radiator stop leaks we recommend:
- Lucas Oil DOT 3 Synthetic Brake Fluid
- Castrol DOT 4 Synthetic Brake Fluid
- Maxima DOT 5 Silicone-base Brake Fluid
- Motul DOT 5.1 Brake Fluid
- Bosch Brake Fluid
- What is Brake Fluid anyway?
- Why is Brake Fluid Maintenance Important?
- Types of Brake Fluid
- How to Change Brake Fluid
- How to Choose the Best Brake Fluid
- These are the Best Brake Fluid Brands
- These are the Best Brake Fluids
- Best DOT 3 Brake Fluid: Lucas Oil DOT 3 Synthetic Brake Fluid
- Best DOT 4 Brake Fluid: Castrol DOT 4 Synthetic Brake Fluid
- Best DOT 5 Brake Fluid: Maxima DOT 5 Silicone-base Brake Fluid
- Best DOT 5.1 Brake Fluid: Motul DOT 5.1 Brake Fluid
- Honorable Mention: Bosch Brake Fluid
- FAQs about Brake Fluid
What is Brake Fluid anyway?
Brake fluid is a fluid used in most modern brake systems, especially those found in the automotive industry. It is used to transfer force from the brake pedal that your foot pushes on, for example, to the brakes on the wheels that actually stop the vehicle.
In other terms, it is a very ingenious solution to link the pedal to the brakes!
And it works because the fluid is non-compressible and thus if we push on it, it will in turn push on the brakes. Contrast that with air which is compressible and thus will not be as efficient in transferring the force when pushed on.
By the way, that’s exactly why brake fluid has to have a high boiling point! When it boils, it converts to gas form, and thus loses its ability to act on the brakes as effectively!
And the boiling point has to be high because the brakes work using friction – converting kinetic energy into heat – and can easily reach temperatures of hundreds of degrees.
Why is Brake Fluid Maintenance Important?
If the brake fluid in your vehicle is not working properly for whatever reason, then the brakes will not work. And you can surely imagine what that would mean for a vehicle running on the road.
Brake fluid, over time, goes bad. It absorbs water from the air, and this causes waste like rust and oxides to build up.
Water also has a much lower boiling point than brake fluid. If you are repeatedly braking really hard, the water might boil in the lines carrying the brake fluid to the brake components. And if that happens, you could lose your brakes and the vehicle won’t stop.
And that’s exactly why brake and brake fluid maintenance is one of the most important activities to perform on a vehicle!
The brake fluid change interval varies, but a good rule of thumb is every other year. When it’s time, you can perform a brake fluid change during your regular oil change maintenance.
It’s also usually not very expensive if you prefer having your mechanic do it. However, as we often recommend, be sure to bring your own fluid so you’ll be sure to be using the best brake fluid on the market for your needs and the service charges will be even lower.
Lastly, if you’re just topping off a low brake fluid reservoir, only use brake fluid from a fresh container. Brake fluid starts to go bad almost immediately after the container is opened and it lasts for about two years in an unopened container.
Types of Brake Fluid
Brake fluids are differentiated according to their DOT level. DOT stands for Department Of Transport, and that’s the department that defines the boiling points of the various DOT levels of brake fluid.
We have four levels: DOT 3, DOT 4, DOT 5, and DOT 5.1.
In general, the higher the DOT level, the higher the boiling point of the fluid.
However, there’s another important difference: DOT levels 3, 4, and 5.1 are glycol-based fluids, whereas DOT level 5 is silicone-based. Glycol-based fluids are the most common, used in 99.9% of vehicles.
You should stick with the DOT level recommended by your vehicle owner’s manual. That will probably be a DOT 4, as that’s the standard for most modern vehicles.
With that clear in mind, however, the previous distinction is important because if your vehicle requires a glycol-based fluid of a certain DOT level (e.g., a DOT 3) you can actually use any equal or higher glycol-based DOT level (e.g., a DOT 3, 4, and 5.1), as they will all be compatible with your brake system. You can even mix DOT levels 3, 4, and 5.1 if you’re so inclined.
But you should never ever use a silicon-based fluid in a brake system requiring glycol-based fluids (and viceversa), as their composition is different and you will ruin your brake system.
How to Change Brake Fluid
A full brake fluid maintenance on your own tends to be a rather long process. Given its low frequency and moderate cost, we actually recommend having it serviced by a mechanic, maybe during a periodic checkup. Be sure to bring your own brake fluid as we said before, to be certain of the quality of the product used and to decrease the service charges.
If, instead, you’re really determined to do it on your own, then this video below will guide you through the process.
How to Choose the Best Brake Fluid
Compatibility is the single most important factor you should consider when selecting the best brake fluid for your vehicle.
First of all, check the vehicle owner manual to find the recommended DOT level. We recommend you stick to this recommendation and then simply get the best brake fluid at that DOT level from the ones we reviewed below.
If, however, you are determined to get a different DOT level, remember what we said before about brake fluid types. Go equal or higher on the DOT level and respect the composition: glycol or silicone. Failure to do so will damage your brake system, so please pay attention.
These are the Best Brake Fluid Brands
Lucas Oil is an all-American manufacturer and distributor of automotive oil, additives, and lubricants. Founded in 1989, this brand has since become a regular presence in most top automotive product reviews. And there’s a reason for that. One of their best products is the Lucas Oil Synthetic Brake Fluid.
The Castrol brand, part of the Wakefield Oil Company founded in 1899, originated after researchers added castor oil to lubricant formulations. Their motto is pretty eloquent: “It’s more than just oil, it’s liquid engineering”. One of their top products is the Castrol Synthetic Brake Fluid.
Headquartered in Southern California since 1979, Maxima is recognized as one of the most coveted brands in the racing industry. Decades of active involvement in professional racing have led to powerful technology and a full array of market-leading products. One popular product is the Maxima Silicone-base Brake Fluid.
Founded in 1853 in New York City, Motul is a French company particularly famous in the racing industry. It develops lubricants for racing cars, motorcycles, and other engines, and its products are available in more than 80 countries. One of their best products is the Motul Dot 5.1 Brake Fluid.
Bosch is a world-famous German multinational engineering and technology company. Their products are world-renowned and available pretty much everywhere on the globe. Their best braking fluid product is definitely the simply named Bosch Brake Fluid.
These are the Best Brake Fluids
Best DOT 3 Brake Fluid: Lucas Oil DOT 3 Synthetic Brake Fluid
Lucas Oil’s is, in our opinion, one of the best brake fluids on the market with its impressive high-quality formulation.
The fluid is compatible with every rubber component of the braking system, and it’s capable of being blended and mixed with other glycol-based brake fluids as well. It protects and strengthens the brakes so they last longer and perform better.
It is our choice for the best DOT 3 brake fluid, as it meets and exceeds the industry minimum dry boiling point of 401 degrees Fahrenheit, can be used both on disc and drum brakes, and can even be applied to the clutch. It protects your brakes against rust and corrosion, prevents excessive hardening or softening of the rubber components, and provides excellent lubricity.
Best DOT 4 Brake Fluid: Castrol DOT 4 Synthetic Brake Fluid
Castrol’s synthetic is our best DOT 4 brake fluid of choice.
Its formula features very high wet and dry temperature ratings. It exceeds DOT 3 and 4 specifications and provides superior braking performance even for race or rally competitions. The product also has excellent anti-vapor lock features and protects the braking system from rust and corrosion.
If you’re determined to perform the fluid change yourself, Amazon offers a convenient combo package with Castrol brake fluid and a bleeder bottle from Allstar.
Best DOT 5 Brake Fluid: Maxima DOT 5 Silicone-base Brake Fluid
Maxima’s is our best DOT 5 brake fluid pick in this review. If you’re looking for a silicone-based brake fluid that meets and exceeds the DOT 5 specification, cools down your brakes quickly, and provides great maintenance service, then Maxima’s racing brake fluid is your best choice.
With superior braking qualities, this fluid was designed for rallying and racing and has an exclusive formula with an exceptionally high boiling point.
We’re going to remind you again to be extra careful with DOT 5 brake fluids as they are designed for selected braking systems that require silicone-based fluids. So be sure to check your vehicle is compatible with DOT 5 before buying it.
Best DOT 5.1 Brake Fluid: Motul DOT 5.1 Brake Fluid
Motul is a favorite brand in the racing industry and its brake fluid is used in a wide range of high-performance cars. It’s not recommended for general passenger vehicles, but if you need top of the line quality, this is the fluid for you.
It exceeds DOT 5.1 requirements and guarantees great performances even under the most extreme usage and temperature conditions. It’s hands-down one of the most recommended brake fluids by racing and rallying enthusiasts, and it deservedly earns the best DOT 5.1 brake fluid pick in our review.
Honorable Mention: Bosch Brake Fluid
Bosch’s brake fluid is an excellent product from the famous German manufacturer.
Simply stated, what earns it an honorable mention in our review is its ultra-wide compatibility and the fact that it is available practically anywhere in the world. This lubricant ships anywhere in the world.
Bosch’s brake fluid has excellent lubricity qualities and exceeds all DOT standards. It can be used with brake systems requiring DOT 3, DOT4, or DOT 5.1 fluids. And with its long change interval of three years, it’s your best bet if you’re not sure of the particular type of fluid that your vehicle brake system requires. Or if you simply prefer a more hands-off approach.
FAQs about Brake Fluid
How often should I change brake fluid?
As with most things automotive, check your vehicle owner’s manual first! It generally contains a schedule based on either time or miles driven to determine how often you need to change the fluid.
That said, the general recommendation is every other year.
What type of brake fluid do I need?
The type of brake fluid required by your vehicle will be written in the owner’s manual. So check that and then buy the best brake fluid for that DOT level.
That said, most modern passenger vehicles require glycol-based fluids, generally matching a DOT 4 specification.
Can I use a different type of brake fluid than what is recommended by my vehicle owner’s manual?
As we explained, brake fluids are either glycol-based (DOT 3, 4, and 5.1) or silicone-based (DOT 5). You must respect the required formulation. So you can’t use silicone-based fluids where glycol-based ones are required, and viceversa.
That said, with glycol-based fluids, you can “go higher” on the DOT level, for example using a DOT 4 or 5.1 when a DOT 3 is required.
Can you mix different types of brake fluid?
You can mix glycol-based brake fluids with other glycol-based fluids even of different (higher) DOT levels. And you can mix silicone-based brake fluids with other silicone-based fluids. What you can’t do is mix glycol and silicone-based fluids as that will damage your braking system.
How often should you bleed your brakes?
Bleeding brakes refers to releasing the air that has built up in the brake system. It’s an important part of regular brake maintenance and can keep your pedal from getting spongy and unresponsive.
It is recommended to perform it every brake fluid change, so generally every other year.
The braking system is a critical module of every vehicle. And while less frequent, it needs regular maintenance as with all other components.
For general passenger vehicles, Bosch Brake Fluid gets our recommendation as the most reliable and widely applicable brake fluid.
If, however, your vehicle has more particular requirements (e.g., a DOT 5 level), check the owner’s manual and then simply get the brake fluid from our review that matches those requirements.