What Causes the Brake Pedal Go to the Floor

Every car owner knows the importance of having a perfectly operational brake pedal. Let’s say you bought a pretty good pedal from the store, but whenever you start the engine, it goes to the floor. Now you might be wondering, what could cause this technical mishap?

There are a few reasons that can cause the brake pedal to go to the floor. To begin with, if the brake fluid leaks, the pedal will become swampy and won’t come up. Also, if the master brake cylinder becomes faulty, the pedal might not work. Moreover, the air inside the brake system can also cause this phenomenon.

I’ve talked about some of the key reasons behind a fallen brake pedal, and now I’d like to provide some valuable insights into this topic. One of the most common questions that I get asked is, “why does the brake pedal go to the floor when the engine is running and here, I will extensively explain it. For a better understanding of this topic, it would be wise to read through the whole article.

Reason Behind Brake Pedal Going To Floor

Now, there can be various reasons behind the brake pedal going to the floor. Below, I will extensively explain the main factors that cause this mishap.

The Leak Of Brake Fluid

One of the most common reasons behind the brake pedal going to the floor is a brake fluid leak. Now, the leak exists somewhere on the brake system, and identifying this problem is pretty straightforward. Whenever you see fluid on the floor of your garage, check for any leaks.

Due to the leak, whenever you press the pedal, the fluid will pour out of the brake system and the air will suck in. That is why the brake pedal won’t come up after pressing.

If Master Brake Cylinder Is Faulty

For those who don’t know, the master brake cylinder is at the opposite side of the brake pedal and it helps reduce the speed of your vehicle by pushing the brake fluids to pistons. It is a very important part of your car’s brake system.

Now, if the sealing cylinder leaks, pressure will be reduced from the padel and as a result, you will feel like you are using a brake pedal that is constantly sinking.

If The Brake System Contains Air

If you have recently repaired the hydraulic brake system of your car, and if you haven’t made any brake bleeding after finishing the job, it might cause the brake pedal to go to the floor.

As you might already know, the brake system of a car needs to be completely free of air to make a high amount of pressure when necessary. So, extra air can interfere with the system’s activity and cause a swampy brake pedal.

Brake System

How To Fix The Issue

I know how frustrating it can be when the brake pedal goes to the floor and becomes unresponsive. Fortunately, the remedy to this problem is pretty straightforward.

Step One

To begin with, you must adequately check all the components of the brake system to find a leak. Commonly, if the brake lines are rusty, a leak occurs. You should properly check the car’s brake calipers, hoses, brake lines, and so on.

Step Two

After that, check whether your car has enough brake fluid. If the brake system has a lower fluid level, the brake pedal will go to the floor.

Step Three

If the first two steps don’t solve the issue, that can mean the battery system has some external air. Bleed the system correctly and the problem should resolve.

Step Five

If you are still facing the issue, simply detach the vacuum hose. It locates on the brake booster. After that, simply try the brake paddle and check whether it works.

Step Six

After performing all of the steps mentioned above, if you face issues, you must break the car’s master brake cylinder. Your only option is to buy a new one as repairing a cylinder might not be possible.


As you can see, brake paddles can become unresponsive for various reasons. “why does the brake pedal go to the floor when the engine is running is a common question, and I have extensively answered it in this article. Hopefully, after reading the whole article, you will find the reason that is causing this issue. Until next time bye.

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