Can You Use Engine Oil As Brake Fluid? – (Explained)

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A hydraulic braking system on any vehicle is much more efficient and highly effective than mechanical wire brakes.

These hydraulic brakes use an incompressible fluid, which pushes the brake pads to decelerate the vehicle.

Visually, the appearance of brake fluids is quite similar to motor oil, but their chemical properties are different.

So, can you use engine oil as brake fluid? Replacing brake fluid with engine oil is not advisable as the chemical and mechanical properties differ. Brake fluids are designed to go under uniform compression and apply consistent pressure on brakes, while engine oil is designed to reduce friction between moving parts. That’s why manufacturers strictly warn to use only specified brake fluids (DOT 3 or DOT 4) in motorcycles.

Filling Brake Fluid Reservoir

Is Engine Oil And Brake Fluid The Same?

No, engine oil and brake fluid completely differ in chemical properties and applications. The engine oil prevents wear on moving parts due to frictional force and keeps the engine cool.

At the same time, brake oil is designed to go under uniform compression and generate constant pressure on the brake pads. You should never replace the brake fluid with engine oil.

Difference Between Brake Oil And Engine Oil

The brake and engine oil are different and cannot be interchanged. Brake oil is designed to transmit hydraulic pressure from the brake lever or pedal to the brake components, such as calipers and wheel cylinders.

On the other hand, engine oil is formulated to lubricate and protect the motorcycle’s internal combustion engine.

It reduces friction between moving parts, minimizes wear and tear, and helps to dissipate heat generated by the engine.

What Happens If I Use Engine Oil As Brake Fluid?

The viscosity of engine oil is different from brake fluid and has different chemical properties. If you interchange the brake fluid with motor oil, it will damage the rubber seal and can cause rubber seals to deform and swell; eventually, that makes your brake sticky, hard to press, leaky, and even may fail.

Related: Why is my motorcycle’s front brake too hard? – Fixed!

What Can I Use As A Substitute For Brake Fluid?

Brake fluids are Glycol-based hygroscopic fluids, which means they absorb moisture.

There is no substitute for brake fluid for effective and reliable braking because brake fluids are designed to go under uniform compression with the desired viscosity and boiling point.

However, if you’re stuck on a road and have no other option, you can use water and soap in an emergency.

But don’t drive fast as they have a low boiling point, and once you reach your home, bleed all the soapy water and refill the specified brake fluid (Dot 3 or 4).

Royal Enfield DOT 4 Brake Fluid

What Happens If You Drive With Dirty Brake Fluid?

Vehicle manufacturers always advise keeping your brake fluid filter clean because any dirt in the brake fluid will prevent the fluid molecules from going under uniform compression.

Eventually, this will apply inconsistent pressure on the brake pads, which can cause uneven wear or damage to your brake pads, which can cause grinding, squeaking, or squealing noises when you press the brake lever.

Can You Drive With Low Brake Fluid?

Generally, the brake fluid has a larger reservoir lasting over two years. However, if there is leakage, the brake fluid level will drop, and you can top-up with specified brake oil.

Driving with low brake fluid is possible, but there is a high chance of braking failure. So, if the reservoir has a low brake fluid level, drive slowly and refill the tank as soon as possible.

Can You Use Automotive Brake Fluid On Motorcycle?

A car uses DOT 3 or DOT 4 brake fluids for hydraulic braking, and a motorcycle uses the same. You can interchange the brake fluids of cars and motorcycles, but don’t mix them (if they have different ratings). There is no issue in mixing brand new DOT 3 with DOT 3 and DOT 4 with DOT 4.

Can You Use Baby Oil For Brake Fluid?

The visual appearance of baby oil is similar to brake fluids; that’s why many riders think they’re interchangeable. But baby oil’s chemical and mechanical properties are totally different, and you can not use that as brake fluid.

The boiling point of baby oil is low, and it can destroy the rubber sealings of hydraulic brakes. If your motorcycle has no brake fluid, fill the reservoir with soapy water for emergencies.

Can We Use Water Instead Of Brake Fluid?

Water molecules can go under uniform compression, an essential chemical property of brake fluids. But, the boiling point of water is low, and it can evaporate quickly.

However, if you’re stuck somewhere on the road, and your brake fluid is low, you can temporarily use water as brake fluid.

But, avoid using too much braking when your brake fluid reservoir is filled with water. Once you reach home, empty the reservoir, bleed the hydraulic brake, and refill the specified fluid.

Is It Okay To Refill The Brake Fluid?

You can top-up the reservoir if your brake fluid isn’t dirt-contaminated. But I generally drain my old brake fluid and refill the new one for consistent and reliable braking.

This is something where I don’t want to compromise, and I also recommend you empty the brake fluid reservoir when filling a new one.


A brake fluid has different chemical properties than engine oil. Although they look similar, you can not interchange them. Using motor oil instead of brake fluid will damage the rubber seals of hydraulic brakes, which can eventually lead to failed braking. Always use DOT 3 or DOT 4 brake fluids in motorcycles and cars.

Enjoy safe rides!

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