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Brake fluid is the core component of any braking system. The entire braking system is dependent on brake fluid. Without it, the system is useless. If somehow the brake fluid level reduces, then that can be quite dangerous for you to drive.

What are the Symptoms of Low Brake Fluid?

You can figure that out by looking out for these five major symptoms, which we will discuss in this article. 

The main signs of leaking brake fluid are fluid underneath a car, the illuminated warning light of the brake, and the brake pedal becoming soft and spongy.

Let’s discuss each sign in detail.

1. Brake Fluid Underneath the Car

The first visible sign that your brake fluid is leaking is the presence of fluid underneath your car. 

Let’s say you have parked your car in a garage. When you unpark it, you will see a yellowish-brown fluid where the car was parked. 

It feels oily to the touch too.

Don’t ever taste it since it is chemically composed of Diethylene glycol (DEG), a toxic chemical compound. An important thing to note is that the leaking brake fluid is often found near the car’s wheels. 

If you follow the path of the leaking fluid, leading you to the master cylinder or brake pipes, then most probably, the brake fluid has leaked. 

Since the brake fluid looks similar to engine oil, people confuse engine oil leakage with brake fluid. 

2. ABS Warning Light

Modern cars now have an ABS brake warning light equipped with sensors present in the braking system. When the brake fluid drops below a certain level, the sensors send the message to ECU and illuminate the brake ABS light.

ABS light

This illuminated red or amber light warns that the brake fluid level has reduced due to a leak.

3. Soft Brake Pedal

Since the brake fluid is the blood of any braking system, a leak causes the brake pedals not to function properly; they become soft, spongy, and less resistant. 

To understand how low braking fluid causes soft brakes, you need to understand the braking system and the role of brake fluid in it.  

Pressing the pedal pressurizes the fluid inside the master cylinder, entering the wheel cylinder. This pressure energizes the brake pistons. Brake pistons move to the sides and apply pressure on the brake pads. The brake pads then rub against the tire, and the brake is applied.

The whole braking system is based on Pascal’s law. The force you apply through the brake pedal changes into pressure inside the master cylinder. Then, this pressure forms an amplified force using Pascal’s law and stops the vehicle.  

Another sign of low brake fluid is the sinking down of the pedal when pressed. You may also notice that the response time of the brake is reduced. The car doesn’t stop as quickly on applying brakes. 

Brake Pedal Creaks when Pushed Down and Released – The Dangers

4. Brake Failure

If you ignore all the above symptoms, and your brake fluid keeps leaking continuously, eventually reaching a point where most fluid has leaked out of the system, the brakes fail. Now, you can imagine how disastrous this can be for you.

5. Brake Fluid Low In Reservoir

You’ll have to pop the hood for this one. The brake fluid reservoir should always be above the MIN line indicated on the side of the bottle. If it’s below this line, it needs to be topped up. It’s important to select the correct brake fluid for your climate

What are the Causes of Low Brake Fluid?

We have discussed the signs showing you if the car you are driving has a low brake fluid. Don’t you want to know what might be the possible causes of low brake fluid? The major causes are leakage in the system, rust, worn-out brake pads, or sometimes the installation of new brake pads.


The most common cause of low brake fluid is leakage of brake lines, master cylinders, pipes, or calipers. The leakage reduces the hydraulic pressure needed to slow or stop the vehicle. Over time the fluid seeps through the holes, and you might see an oily yellowish fluid under your car. 

Worn Brake Pads

Worn-out brake pads can also utilize more brake fluid. When the brake pads wear out over time, the caliper piston travels a larger distance to reach the brake pads. This way, more brake fluid is pushed, and the level reduces.

Rusty Brake Lines

Since the brake system consists of metallic components, these components rust over time. This causes the brake fluid to leak through those rusted pores and allow air to enter the brake fluid on rare occasions. Brake fluid itself has anti-corrosive additives, but these separate in the older fluid.

Brake Pads Replaced

Whenever you overhaul your engine, do you use the old engine oil? Of course not. Although you replace your brakes more often than you have work done on the engine, it’s still good practice to replace the fluid simultaneously.

Whenever a hydraulic system (brake system) is opened, it gets exposed to air and impurities.

So, there is a risk that the brake fluid may have leaked or been contaminated. It is advised that whenever you replace your brake pads, drain the brake fluid and refill the system with new.

Ensure the brakes are bled and all the air purged out of the system, too.

Air In The Brake Lines

Having a hole in the brake line also lets air into the system. Air disrupts the flow of brake fluid and, more importantly, can’t be compressed as well as brake fluid. This makes braking less responsive.

Can I Drive with Low Brake Fluid?

It is not advisable to drive the car if you see these signs of low brake fluid. If the leaking is very bad, the whole system can be drained quickly, resulting in a sudden brake failure. 

It can be fatal for you and other people driving on the road. Don’t risk it. 

So, whenever you notice the signs of low brake fluid, you must fix its cause as soon as possible. In this way, you can ensure your safety and others’ driving on the road.

Many visitors also read these related articles:

Can Dirty Brake Fluid Cause Squeaky Brakes? [ANSWERED]

Why Do Brakes Squeak in The Morning? Help & Advice

In Conclusion

One or more of the following signs and symptoms may be present if your brake fluid is causing a problem:

  • The brake warning light illuminated.
  • Brake fluid is low, thick, or black.
  • The brake pedal is soft.
  • Brakes take longer to stop.

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