Brake Pedal Goes to Floor: What Causes It and How To Fix It

by

Brake pedal goes to floor after depressing it, don’t ignore it; this is a sign that the braking system is faulty. The importance of brake pedals in saving lives and property can’t be overstated; thus, you need to take action to rectify the situation.

Brake Pedal Goes to Floor

We’ll discuss why your brake pedal becomes spongy and how to fix it. We’ll then answer some pertinent questions about keeping your brakes in tip-top condition.

What Makes the Brake Pedal Go to the Floor When Pressed?

The brake pedal will go to the floor when pressed because it has lost its internal pressure, which several issues can cause. Issues like brake line leaks, faulty brake master cylinder, damaged brake booster, air in the brake lines, caliper leak and lack of brake fluid.

Usually, when you depress the brake, the brake liquid forms a slight resistance to your action. As you overcome the resistance, the car gradually comes to a stop. However, when that slight resistance is absent, the brake pedal will hit the floor immediately. When this happens, the vehicle won’t stop, which poses a danger to the driver and other road users.

  • Brake Fluid Leaks Through the Brake Lines

The brake lines transport the hydraulic pressure through the brake fluid to the wheel, where they apply pressure to the brake pads in a disc brake system. This pressure slowly stops the motion of the wheels.

 

However, if there’s a leak in any part of the brake lines, the fluid won’t generate enough pressure to press the brake pads against the wheels. Thus, the brake pedal sinks to the ground, resulting in brake fluid leaking off the lines and onto other vehicle parts.

  • A Faulty Master Cylinder Failing to Transmit Enough Pressure

When you apply pressure on the brakes, the master brake cylinder converts the mechanical energy to hydraulic pressure. It then transmits the hydraulic pressure through the brake lines to the brake pads, which exerts a frictional force on the wheels.

However, a malfunctioning master cylinder may fail to convert the mechanical energy or significantly reduce the hydraulic pressure. Thus, the brake pedal will go straight to the floor when depressed.

  • When Air Gets Into the Brake Lines

When air gets into the brake lines, it obstructs the flow of the fluid and reduces the hydraulic pressure applied to brake pads. Thus, the brake pedal feels spongy or sinks to the floor whenever you step on it.

Faulty Brake Pedal

One way air sneaks into the brake lines is improper bleeding after replacing the master cylinder. Another way is when you don’t bleed out the brake lines correctly after changing them.

Air bubbles in the brake system are dangerous, which is why you need to get them out the right way. The process of getting rid of them is termed bleeding and is quite complicated. Thus, we recommend you allow a mechanic to do it for you.

  • A Bad Brake Booster

The brake booster amplifies the force needed to stop the car. It makes the brakes work easier and prevents the driver from exerting more mechanical force. The booster is between the brake pedal and the master cylinder and uses a vacuum system to enhance its operations. Thus, when you press the brake pedal, the booster multiplies the pressure through the vacuum system on the lever connected to the pedal.

The lever then applies the amplified force on the master cylinder, which transfers it to the brake pads through the lines. A booster cannot multiply the force to stop the wheels when it becomes faulty. Thus, the pedal goes to the floor or has a spongy feel when you step on it.

  • A Leaky Brake Caliper Allows the Brake Fluid to Seep Out

A leaky brake caliper will allow the brake fluid to flow out, reducing the hydraulic pressure needed to halt the car. After pressing the brake pedal, the brake fluid flows from the brake system to the caliper.

The hydraulic pressure from the brake fluid forces the calipers against the wheels and stops the car. If the caliper has a broken seal, the fluid will seep out and decrease the hydraulic pressure across the braking system. Thus, you must press the brake pedal to the floor to slow down or stop the vehicle.

  • Inadequate Brake Fluid in the System

Since the brake fluid is the main player in stopping a vehicle, the lack of it will affect the braking system. The brake fluid carries the hydraulic pressure that forces the calipers against the wheels.

However, the brake fluid volume must be up to standard for the hydraulic pressure to be effective. If the volume is below the required level, the hydraulic pressure won’t be effective, causing a sinking brake pedal.

Braking systems lose their fluids through attrition or leakage in any part of the system. Thus, you’ll have to determine the main cause of the brake fluid depletion before attempting to fix it. For instance, it won’t be wise to top up the fluid if there’s a leak in the system.

  • Sediments in the Brake Fluid

Sediments in the brake fluid can interfere with the hydraulic pressure and speed up its natural attrition. These pieces of debris can get into the system during a brake pad replacement or during bleeding. The sediments can even obstruct fluid flow in the brake system. Worse still, the debris can damage the master cylinder, causing it to malfunction.

How To Fix a Brake Pedal That Goes To The Floor

To fix a brake pedal that goes to the floor, you need to diagnose what is causing the problem. You can decide the most effective way to tackle the problem from there. If you have soft brakes or they feel spongy due to debris, you must bleed them.

You can also bleed your brakes when there are air bubbles in the fluid, or the fluid has degraded and needs replacement. However, you must enquire which brake fluid is perfect for your vehicle. Some brake fluids don’t mix well and may cause damage to the braking system.

Also, check from your car manual the correct volume of brake fluid your system needs. Next, gather the right tools for the job, including safety equipment, and start the process.

  • How To Bleed the Brakes of Your Car

First, support your vehicle with four jacks by placing each near the four wheels and remove the wheels. Loosen the four bleeding screws on each caliper without removing them because you’ll be bleeding one at a time.

Fix a Brake Pedal in Car

Next, locate the master cylinder reservoir under the hood of the car and check brake fluid to see if it’s enough, and top it up if it’s not. Ensure you bleed the brakes in the right sequence, as illustrated in the car manual.

Connect one end of a tube (hose) to the bleeder screw of the first caliper and the other end to a container. Ensure the container is above the level of the screw to prevent air trapped in the hose from getting into the caliper. Let someone sit inside the car and pump the brake pedal several times until they feel a strong resistance.

When the assistant achieves a strong resistance, he should shout “Pressure,” and then you open up the bleeder screw to allow brake fluid to flow into the container. The person should maintain pressure on the pedal and keep pushing it toward the floor, which will force the brake fluid into the container.

When the pedal almost touches the floor, the person should shout “floor,” then you should quickly close the bleeder screw and check the liquid level in the master cylinder. If it is depleted, top it up and repeat the process of pumping the brake pedal until the stream of air bubbles flowing through the tube stops. Do this on all four wheels until you’re convinced that the air bubbles or sediments are out of the brake system.

  • How To Replace a Master Cylinder in a Braking System

First, you need to locate the master cylinder, which is usually under the brake fluid reservoir. If you don’t find it there, consult your car manual for the precise location. Next, siphon the brake fluid from its reservoir and dispose of it according to the local laws. Pull out the brake fluid sensor connector and unscrew the brake fluid lines with a wrench.

Now, unscrew the bolts that hold the master cylinder in place and remove the device. Install the new master cylinder and fasten the bolts to secure it in place. Pour brake fluid into the reservoir and let it run through the brake pipe holes. Let someone sit behind the steering wheel to press the brake pedal while you hold a container under the holes to catch the fluid.

Connect the brake lines and the brake fluid sensor, and then bleed the master cylinder. Bleed the brakes as well to get rid of air bubbles that may be trapped inside the fluid.

Frequently Asked Questions

– How Can You Maintain Car Brakes?

To maintain car brakes, constantly check the brake fluid level and top up if necessary. Also, replace the brake fluid according to the schedule in the car manual. Check the brake shoes, the master cylinder and the brake lines for any damage and replace them if necessary.

– What Are the Signs of a Failing Brake Master Cylinder?

The signs of a failing brake master cylinder include a spongy feel when you step on the brakes, the brake warning light will illuminate, and the brake fluid will leak. Other symptoms include reduced braking power, contaminated brake fluid and illumination of the check engine light.

– What Are the Symptoms of Air in the Brake Lines?

The symptoms of air in the brake lines are spongy brakes, brakes sinking to the floor when depressed, and increased braking distance. Usually, the brakes are not as effective as they were, leading to accidents. The best way to solve this problem is to bleed the brakes.

Brake Master Cylinder

Conclusion

We’ve discovered the reasons the brake pedal goes all the way to the floor after the new master cylinder and how to find ways to rectify the situation.

Here is a recap of all that we’ve discussed:

  • The reasons why your brake pedal will go to the floor include leakage in the brake lines, a bad brake master cylinder, air bubbles in the brake lines and a malfunctioning brake booster.
  • Other issues like leaky brake calipers, inadequate fluid in the braking system and sediments in the brake fluid can cause your pedal to sink to the floor.
  • To remove air bubbles and sediments in the braking system, you must bleed the brakes, but the other causes, like a broken master cylinder and brake booster, require replacement.
  • You should also bleed the brakes when you replace your master cylinder and brake booster and replace brake fluid to ensure the system functions well.
  • Bleeding the brakes is tricky; thus, we recommend you contact a professional to help you if you don’t have any experience.

Signs that indicate your brake pedal is spongy are the illumination of the brake warning and check engine lights, reduced braking power, and brake fluid contamination. To maintain a healthy braking system, always check the brake pads and master cylinder for any damages.

5/5 - (15 votes)
Ran When Parked
Latest posts by Ran When Parked (see all)