Low Brake Fluid Symptoms: All 5 Explained

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Low brake fluid is much more common than you think since so many factors can influence its quantity, but what are the low brake fluid symptoms you need to look for?

Let us go through the low brake fluid symptoms as the fluid gets lower and lower:

  1. The brake light will come on.
  2. The brake fluid is below the minimum mark on the brake fluid reservoir.
  3. The brakes will start feeling spongy.
  4. The vehicle’s brake distance will start increasing.
  5. The brake pedal will have no resistance and fall to the floor.

With the symptoms laid out, let us go over them and discuss why it happens.

a man pointing at the fill neck of a brake fluid reservoir

5 Low Brake Fluid Symptoms

1. Brake Light Is On

The brake light will illuminate when the brake fluid reaches the reservoir’s minimum mark.

At this point, the best thing to do is to drive to the nearest parts store or garage and buy the correct DOT brake fluid for your car.

Remember that car manufacturers usually design the brake system when the brake light comes on, and it is because of low brake fluid that the brake pad life is also near the end of life.

There can also be four other reasons why the brake light is on.

2. Brake Fluid Is Below Minumim Mark

If you routinely inspect your engine bay, you will see that the brake fluid level in the brake master reservoir will be on or below the minimum mark.

Try to avoid driving at this point because topping off brake fluid is much easier than rebleeding the system if the master cylinder happens to pull in an air pocket.

Take another vehicle, ask a friend or family member to get your car brake fluid with the correct DOT rating, or order it online.

3. Brakes Feel Spongy

If the brake light and low brake fluid are ignored, and the brake fluid level gets too low, the brake master cylinder can easily pull air into the system when you use the brakes.

Every time you press the brake pedal, the master cylinder takes fluid from the reservoir and compresses it into the brake lines.

If there is too little brake fluid, the master cylinder runs dry and grabs air into the system.

As we learned in school, air is much more compressible than fluid; thus, the brake pedal will be easy to push if there is air in the system.

This will give the brake pedal a spongy feeling, drastically lower the brake fluid’s boiling point and cause brake fade when applying the brakes over a long time or distance.

4. Brake Distance Increases

As the air in the system increases, the brake performance decreases because the master cylinder can put less force on the braking system since it struggles to compress air.

At this point, the brake pedal will need to be pumped numerous times before there is an indication of the car slowing down.

A total rebleed of the system is necessary at this point, and driving is hazardous because you can’t do an emergency stop if necessary.

5. Brake Pedal Falls To The Floor

When the brake pedal goes to the floor with no resistance, there is almost no brake fluid left in the system.

At this point, the vehicle has no hydraulic brakes; the only working brake is the parking brake.

So if you are driving at this point, start downshifting the vehicle and slowly apply the parking brake until the car stops and get someone to tow the vehicle to a workshop or your house.

What Causes Low Brake Fluid?

Numerous reasons can cause your vehicle to have low brake fluid:

1. Brake Fluid Leak

This can either be at a fitting at the master cylinder to the hard lines, in the wheel wells the fittings from the hard line to the soft line or the fittings from the soft lines to the brake calipers.

The soft line in the wheel wells can also get damaged if the clips that hold it out of harm’s way break.

The soft lines can easily be rubbed through by the tire or get pinched between the suspension components, resulting in leaking fluid.

The hardlines can also develop rust over time and start leaking or getting mangled by road debris or offroading.

2. Worn Out Brake Pads

As the brake pads wear down, the brake system needs more fluid to expand the caliper or drum brake pistons.

As mentioned at the beginning, car manufacturers design brake systems these days, and the brake light on the dashboard will indicate that the brake’s lifespan is almost depleted and will need replacing.

3. Worn Out Brake Master

When the brake master cylinder is worn out, the seals inside will start seeping brake fluid into the brake booster.

This is an infrequent occurrence as the seals and brake fluid used in modern vehicles are better designed, and brake fluids like DOT 5 are now silicone based, making them less abrasive on rubber and plastic components and won’t even eat away car paint like DOT 3 and 4.

a man topping up brake fluid in a red car

Final Thoughts On Low Brake Fluid Symptoms

No one wants to experience losing brake performance, so to avoid these low brake fluid symptoms, do routine checkups on the vehicle’s fluid levels.

I recommend going through the fluids once a month and always using the correct fluids, from brake fluid to radiator coolant.

Hopefully, you found this article helpful and will quickly recognize the symptoms of low brake fluid in the future.


What Happens If Brake Fluid Is Low?

When the brake fluid is low, it will activate the brake light or ABS light on the instrument cluster, make the brake pedal feel spongy and unresponsive, the braking distance will increase, and can also result in no brakes at all if there are very little or no brake fluid.

Can I Just Add Brake Fluid?

Yes, but always inspect and see why the brake fluid has lowered to this point.
It can be from a leak, worn brake pads, or a worn-out brake master cylinder.
Always top up your brake fluid with the correct DOT-approved fluid for your vehicle.

Can I top Up Brake Fluid Myself?

Yes, it is one of the most straightforward automotive maintenance jobs you can do.
Make sure you can identify the brake fluid reservoir; if you can’t find it, your car’s user manual will show the exact location and what fluid to use.
Here is a very easy-to-follow video on how to check and top up your brake fluid:

How to Check Your Car's Brake Fluid