Is Motorcycle Brake Fluid Different From Car? (Or Same?)

Is Motorcycle Brake Fluid Different From Car? (Or Same?)

Both motorcycles and cars use brake fluids as part of their braking systems.

Do these brake fluids match and are one and the same is the question.

Is motorcycle brake fluid different from car? There is no difference in the motorcycle brake fluid and the car brake fluid. The motorcycle and the automotive fluid are one and the same. If both the car and the motorcycle have the same DOT ratings, then they essentially use the same brake fluid in them.

Let us deep dive into the specifics of the brake fluid used in these vehicles.

Is Motorcycle And Car Brake Fluid The Same

There is no difference in the motorcycle brake fluid and the car brake fluid. The motorcycle and the automotive fluid are one and the same.

Both the car and the motorcycle use the same brake fluids.

A DOT4 brake fluid used in a motorcycle is exactly the same DOT4 brake fluid used in a car. There is no difference in the brake fluid at all.

Within the brake fluids, there are different types – DOT 3, DOT 4, DOT 5, DOT 5.1 etc.

These type of brake fluids have different boiling points and usability.

However, a DOT 4 recommended in a motorcycle and a DOT 4 recommended in a car will use the same DOT 4 brake fluid.

There is absolutely no distinction between these brake fluids used in the car and the motorcycle.

If both the car and the motorcycle have the same DOT ratings, then they essentially use the same brake fluid in them.

Different Brake Fluid Types

The brake fluid is classified and rated by a number preceded by DOT.

The ‘DOT’ here refers to Department Of Transportation. And the number represents different type and boiling points.

Higher the DOT number, higher will be the boiling point of the brake fluid.

In other words, a DOT 5 has a higher boiling point than a DOT 3 or a DOT 4.

Here is the boiling point of different brake fluids.

Brake FluidDry Boiling pointWet Boiling Point
DOT 3401o F / 205o C284o F / 140o C
DOT 4446o F / 230o C311o F / 155o C
DOT 5500o F / 260o C356o F / 180o C
DOT 5.1518o F / 270o C374o F / 190o C

The DOT 4 brake fluid is the widely used fluid in motorcycles. Within DOT 4 there are different sub types like – DOT 4 Plus, DOT 4 Low Viscosity, DOT 4 Racing etc.

While a DOT 3 or a DOT 4 absorbs water, a DOT 5 does not. DOT 3 and DOT 4 eat paint as well.

On the flip side, the better characteristics of DOT 5 comes at a cost as it is highly expensive – 4x times than DOT 3.

Here are a few thumb rules to follow regarding brake fluids.

  • Do not mix brake fluid types. A DOT 5 is strictly not allowed to mix with any other fluids. While DOT 3 and DOT 4 are technically mixable, it is still NOT recommended since they can react badly and corrode the brake system.
  • Do NOT use DOT 3 in your motorcycle since its boiling point is too low. The brake system might not work properly with DOT 3.
  • Choose the right brake fluid based on the manufacturer’s recommendation from bike owner’s manual.
  • Change the brake fluid every 2 years. Completely drain the existing fluid and replace with a new one.

Can I Mix Old And New Brake Fluid

It is NOT recommended to mix the old and new brake fluid.

This is because, the moisture and the water content absorbed by the old brake fluid will still exist in the braking system if you mix the old and new brake fluids.

The contaminated particles that have infiltrated the fluid is going nowhere unless drained out. And the performance of the old brake fluid which has deteriorated won’t change and will continue with the poor performance.

As long as the old and existing brake fluid still remains in the system, the braking performance won’t be improved drastically. In addition, after some time, the existing old brake fluid will actually deteriorate even further in quality.

That’s why, the old and new brake fluid should not be mixed. The topping up is fine if the brake fluid is not too old. However, it is always advisable to not mix and drain the old fluid completely before filling up with the new one.

How Often Should You Change The Brake Fluid In Motorcycles

The ideal change interval for brake fluid in a motorcycle is 2 years.

This is mainly because the brake fluid absorbs water and overtime the water content in the brake fluid will start corroding the metal components associated with the braking system.

For a detailed description, check out our post on frequency of brake fluid change.

Is All DOT4 Brake Fluid The Same

The Dot 4 brake fluid in a motorcycle and the DOT 4 brake fluid used in a car or any other automobile – are all the same.

A DOT 4 brake fluid used in any automobile will be of the same characteristics and boiling point. There is no difference at all between the DOT 4 fluid used across different automotive.

Within DOT 4, there are different brake fluids like DOT 4 Plus, DOT 4 Low Viscosity, DOT 4 Racing etc. These fluids are slightly different though with differing boiling and hygroscopic characteristics.

How Do I Know What Type Of Brake Fluid I Have

If your motorcycle brake fluid has not been changed since you have bought it from the manufacture, you can easily get to know the brake fluid type by checking the owner manual.

In the bike’s owner manual, go to the Specifications section and scroll through to check the brake fluid.

Brake Fluid - Owners Manual

If you have changed the brake fluid either by yourself or your dealer or service shop, then you need to recall the brake fluid used or check with your dealer on which type they have used on your motorcycle.

How Do You Know If Your Motorcycle Brake Fluid Is Bad

If you are not able to apply brakes smoothly and are facing braking issues in your motorcycle, then the motorcycle brake fluid has degraded in quality and performance.

When the brake fluid is bad and deteriorated in its quality, you need to replace the fluid with a new brake fluid.

A bad brake fluid will have absorbed water and contamination which has deteriorated its performance and functionality.

So, change the fluid as soon as you find the brake fluid is bad.

Conclusion

The motorcycle brake fluid is same as car. Both these automobiles use same types of brake fluids.

Within brake fluids there are different types – DOT 3, DOT 4, DOT 5 etc.

Use the recommended brake fluid for your motorcycle and never mix one brake fluid type with another.