Brake Pedal Goes to Floor When Engine Running [Causes and How to Fix]

If you have to press the brakes hard or the car’s brake pedal goes to floor when engine running, then there’s something wrong with the brake! A brake pedal is there to help you to stop your car immediately or whenever you want.

There might be some lacking or loss of brake fluids. It can even be a faulty brake master cylinder or faulty brake booster. Sometimes your driving skills can also cause brake problems. But you can solve it by checking brake fluids, brake lines, and brake calipers. An electric parking brake is another good option to avoid such issues.

What Does That Even Mean? (Brake Failure or Loose Brake?)


You may have faced the problem but don’t know how to explain it in words. Actually,
what does it mean when the brake pedal goes all the way to the floor?

It indicates that there is a problem with brake lines, calipers, or master cylinders. You can’t stop your car because of loose brakes or the sponginess of pedals. 

Causes of Brake Pedal Going to The Floor


It’s a pervasive problem that a
brake pedal is hard when the car is off, then soft when the car is on. Well, the reason could be losses of brake fluids or any leaks in the brake fluid pipe. A master cylinder that malfunctions is another potential reason.

You may also experience that sometimes the car’s brake pedal slowly goes to the floor while the engine is running. There are some other reasons for that besides the mentioned ones. So, without any chitchat, let’s dig into the details.

Loss of brake fluid


The
Brake pedal goes to the floor when the engine starts! The vehicle may be in loss of some brake fluids because of leaks in the pipe. Usually, when the brake calipers break or get loose, the brake pedal will lose the power to function correctly.

Technically, the cylinder compression creates high pressure on brake fluid, and it causes the necessary friction on the brakes to stop a car. So, without proper friction, any brake pedal will go to the floor when running.

Lack of brake fluid


Does the
brake pedal go to the floor but have no leaks? Now, it’s time to look into the brake fluid indicator because the vehicle may be lacking brake fluids. There won’t be sufficient friction for stopping the car.

It is also possible that the car’s brake pedal goes to the floor when the engine is off. So, you need to check the indicator regularly, or else you might be in trouble in the middle of driving.

Faulty brake master cylinder


As you know, a master cylinder passes the pressure from the piston and creates high pressure. So, it needs to stay in proper condition. 

If a master cylinder doesn’t work at full scale, it can’t create enough pressure on the brake fluids. Moreover, the car’s brake pedal may go to the floor when the engine is running abs because of a faulty master cylinder.

The damaged master cylinder creates several bypass leaks, and the brake fluids flow in those directions, so no pressure or friction can be created in brake sections.

Faulty brake booster


If you notice your car’s
brake pedal sometimes goes to the floor, or your stopping distance has been increasing gradually, your faulty brake booster can be the reason for it. There might be a vacuum created between the pedal and master cylinder that causes the release of pressure of the brake fluids.

Even a brake pedal can go to the floor only when the engine is running because of this faulty brake booster.  And then, the brakes won’t have enough power to stop your car immediately.

Presence of air in brake lines


It’s not so unusual that
after the new master cylinder, the brake pedal still goes to the floor. But why? It’s because there may be some air present inside the cylinder that is not bled out. The air even brings the sponginess of the pedals and loses the firmness.

The air will damage the brake line, and it will pump up when the brake pedal goes to the floor. As air can be compressed, it can create difficulty while creating high pressure for brake fluids. 

How Do You Fix Brake Pedal Goes to Floor When Engine Running?


When a brake pedal has sponginess, it gives you the feel like
no brake pedal is present when a car is running. It’s too risky to continue driving before fixing the problem.

Check the Brake Fluid Level in The Can


We suggest checking the brake fluid at first whenever you are having such a problem. That is because it’s the most obvious reason for brake pedals going spongy. 

When you notice a comparatively lower level of brake fluids, check if the container is empty or not. Also, check for leaks and repair them.

Check the Brake Lines


If you don’t notice any leakage, then you should look over to the brake line. When your car have a full brake pedal when the engine is off but goes to the floor when running, a damaged brake line may leak out all the fluids and make a spongy pedal.

Sometimes oil residues cause the problem in brake lines and damage them. So, repair the lines as soon as possible.

Check the Brake Calipers


Brake calipers can also cause pedals to go spongy and touch the floor. Therefore, you have to check all the brake calipers from each of the four wheels, along with the bleeder screws.

If you notice carefully, you will see some residues or fresh fluids all the way to the calipers. So, get to a repair shop and fix the brake calipers.

Check the Brake Master Cylinder


Suppose you own a
Jeep Cherokee and its brake pedal goes to the floor when the engine is running, but you can’t find any problem in brake lines or calipers. Your last option is to check the engine’s master cylinder.

You will see oil seals inside the cylinder to prevent the fluids from bypassing. When the seals are loosened, all the fluids choose the bypass, and there won’t be any friction in the brakes.

Electric Parking Brake


It’s a modern solution for the problem of your brake pedal feeling a bit spongy when your car is running. The electric parking brake can provide extra pressure release of the brake whenever you slip the clutch or press the accelerator.

The hill-hold function is another fantastic feature of the EP brake that allows the car to detect any stationary or slope position. You won’t see any HONDA or FORD brake pedal that goes to the floor when the engine is running if you have the latest version.

Most modern cars are trying to implant the EP brake in their engine to avoid facing such problems.

Frequently Asked Questions (FAQs)


How Do I Know If My Brake Booster or Master Cylinder Is faulty?


You can start by releasing the vacuum hose and press the brake tightly. It’s for checking the brake booster. 

If you notice no trouble with the brakes, then your brake booster is faulty. Again, if you see the problem still remains, then it’s the defective master cylinder.

How much will a brake system repair cost?


A complete repair of the brake system along with cylinders and calipers may cost you $700 to $800. But you can do it at a max of $300 if you have to just replace a master cylinder.

Why is there no pressure in my brake pedal?


If you find no pressure in a brake pedal, the reason could be a leakage in your brake system or any faulty component. But the most prevalent cause is a defective brake booster with vacuum leakage.

Why Do I Lose Brake Pressure When I Start My Car?


If you lose the brake pressure after starting the car, your brake system may have lost brake fluids, or there are no brake fluids. But a malfunctioning master cylinder can be the reason if you don’t see any problem with brake fluids.

What do you do when the brake pedal goes to the floor?


The first duty is to look over the brake fluid indicator to verify whether there’s any lacking. Don’t try to drive in the meantime. If you don’t find any fault in brake components, release the vacuum hose and check for a malfunctioning master cylinder.

Why Does My Brake Pedal Go to The Floor After Bleeding?


When you bleed the air from brake fluids, the brake pressure will go out of line. So, you have to press the brakes hard to maintain the pressure to get back the brake line.

Conclusion: Brake Pedal Goes to Floor but Still Stops the Car


Friction is very important in any brake pedal because it’s the primary component of stopping a car. But if the car’s
brake pedal goes to the floor when the engine running, it is definitely not good news.

We have discussed all the reasons and possible solutions so that you can take immediate action whenever you are in such situations. Drive safe and take good care of your car!

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