Brake Pedal Goes to Floor When Engine Running or Starts

Brake problems faced by most drivers are the number one reason for vehicle breakdowns and accidents. Most drivers experience brake failure at least once in their lifetime. Brakes can fail unexpectedly, without warning signs or symptoms, and can be costly to repair.

There are many different types of brake problems. The most common is the failure of the pads to create friction with the rotor and the failure of the brake lines to transmit pressure. The other types include corrosion, air leaks, broken seals, worn cables, and tire damage.

Other problems can leave you stranded or result in costly repairs, but when your brakes start to fail, the only thing you need to worry about is your safety.

There are many factors that can cause the brake pedal to hit the floor. Here are some of the most common causes:

The most common causes of the brake pedal hitting the floor are a faulty brake fluid level, a brake system leak, or a failure of the anti-lock brake system / ABS.

Brake Pedal Goes to Floor When Engine Running

The driver presses the brake pedal to bring the car to a stop. However, when the engine is running or starting, it may occasionally hit the floor. There are many reasons for this phenomenon. The following are some of them:

1. brake fluid leakage

One reason your brake pedal hits the floor is due to a brake fluid leak. Brake fluid leaks can be due to a rusty brake line, but there can also be other reasons, such as worn pads or even a faulty caliper.

A common sign of a brake fluid leak is a puddle of fluid on the garage floor, which may seem trivial at first. However, brake fluid leaks can also cause major damage to your car’s brake system. Fortunately, there are several telltale signs of brake fluid leaks that you can spot.

2. Defective brake master cylinder

Your brake pedal is a vital part of the operation of your vehicle. It transmits the force with which you are pressing the brake to your master cylinder, which in turn pressurizes the brake fluid to activate the brakes.

The brake pedal pushes on this rod which is connected to the master cylinder. This compression of hydraulic fluid generates pressure in the system that applies pressure to all four tires and brings them to a stop, allowing you to stop quickly and safely even when going very fast.

A braking system is an important safety mechanism for an automobile. It requires regular maintenance to ensure that the car can stop efficiently. The master cylinder is one of the most important components of any brake system, as it maintains pressure on the brake fluid so that it can be distributed to the rest of the system. If there is no sealant properly installed in the master cylinder, brake fluid can quickly leak out, causing the car to lose its stopping power.

3. Faulty brake booster

The brake booster is a device that increases the force applied by the engine to the brakes of a vehicle. It is located between the brake master cylinder and the brake pedal. The vacuum creates a vacuum in the piston area of the vehicle’s braking system, which increases the pressure on the piston and pushes it against its seals. The increased pressure will cause an increase in braking efficiency, which means it can stop.

The brake booster takes some of the vacuum pressure created by engine movement and uses it to assist braking. Some vehicles, such as older vehicles, do not have this device. If you’ve ever driven one without it, you’ll know how much pressure is needed without it.

4. Presence of air in the brake lines

If there is any air in the brake lines, after replacing a master cylinder, the driver is likely to experience a sunken brake pedal. The reason for this is that there is air in the brake lines, which must be vented before it will function properly. One way to bleed this air is to use a pressure bleeder designed to bleed.

Air is a major problem for brake systems. Air reduces the pressure inside the brake line, resulting in soft, spongy brakes. Air can enter brake lines due to leaks, improperly sealed bleed valves, improperly installed wheel cylinders, faulty hoses or improperly seated brake drums. Air bubbles often form at the joints between hoses and cylinders because these are the weakest points in the system.

5. Low brake fluid level

Brake fluid is an essential part of your car’s braking system. If fluid levels are not properly maintained, your car’s stopping power can be compromised, which could lead to a potential accident. If you have a brake fluid level warning light on your dashboard, check the brake fluid level as soon as possible.

When brake fluid levels drop, air can enter the brake system. Air in the system can cause many adverse effects, such as long stopping distances and increased pedal travel.

It is always a good idea to check the brake fluid level from time to time. If the brake fluid level is too low, it can become contaminated with air after driving for some time. If this happens, you should bleed the brake system to remove air bubbles.

How do you fix the brake pedal going to the floor when the engine is running?

Look for external leaks: When you don’t know the source of a leak, the best place to start is under your car. Inspect brake lines, hoses, and calipers for signs of leaks. Brake fluid will often leak from these areas if there is any damage or wear to them.

Check the brake fluid level

The brake fluid reservoir is located in the engine compartment and is a translucent plastic container with a black rubber tube leading to the brake system. If the fluid level is low, there is a possibility that there is air in the brake system. Check it.

Bleeding the brake system

Bleeding the brake system is a safety precaution that all drivers should take to avoid brake lockup. The process of bleeding the brakes is relatively simple and can be done with basic tools.

Disconnect the vacuum hose from the brake booster

When you have a vacuum leak, it can make your brakes feel soft or spongy. If you disconnect the vacuum hose from the brake servo and press the brake pedal again, and if that doesn’t work, you most likely have a problem with your master cylinder.

Check or replace the master brake cylinder

A brake master cylinder is a device in the brake system that helps you stop your vehicle. It is important not to overlook or ignore any signs of potential damage to the seal. If you remove the cylinder and find damage, you will need to replace it.

When replacing the master brake cylinder, it is important to inspect the seal for damage. This is because, if there is any damage, you will need to replace the entire unit and not just the seal.

Liam Dare

As CEO of, my passion for the automotive world motivates me to build online businesses that provide information and entertainment to users. I am proud to contribute in a positive way to the automotive community.