How to fix a spongy or soft brake pedal

What causes a spongy or soft brake pedal (and how to fix it)

A system that is meant to keep you out of crashes is your car’s brakes. So what causes a spongy or soft brake pedal? Well, read more to know. You run a high risk of not stopping in time if your brakes aren’t functioning properly.

Because of this, a spongy brake pedal ought to be concerning. Everyone who drives a car is aware of how pressing the brakes should feel. The feel of a soft brake pedal differs slightly from that of a spongy brake pedal.

What causes a spongy or soft brake pedal (and how to fix it)

When you press down on the brake pedal, brakes that are spongy make you feel like you’re pushing against a spring. A soft brake pedal, on the other hand, either drops to the floor or drops too easily.

You should never play around with a spongy or soft brake pedal. It’s critical to identify the root cause of a soft or spongy brake pedal and address it without delay to prevent your car from losing all braking ability.

Well, in this article, you’ll get to know the most common causes for a spongy or soft brake pedal, whether it’s safe to drive with a spongy or soft brake pedal, and how to fix the problem.

Read more: The cheapest places to get your brakes done

Let’s get to it.


What causes a spongy or soft brake pedal?

Below are the most common causes of a spongy or soft brake pedal:

Air in the Brake System

The most common cause of a spongy brake pedal is most likely air in the brake system. When the caliper is overheated and the braking fluid boils, air can enter the system. When air enters the brake lines, the fluid does not flow properly. There would most likely be air in the system if rapidly pumping a gentle pedal restored pedal pressure.

Consider replacing or cleaning the brake fluid if you detect soft or spongy brakes. Flushing brake fluid removes air from the brake system and is also known as bleeding the brakes. Air can get trapped in a system if it is not thoroughly bled after replacing a component.

Over time, brake fluid can collect moisture. To avoid boiling old fluid, which would result in a low brake pedal, you should flush the brake fluid regularly. The ABS (anti-lock brake system) and the master cylinder, among other brake components, will be safeguarded and preserved by fresh, clean fluid, ensuring their long-term, trouble-free performance.

Broken brake lines

A broken line may have been one of the ways air entered the system. Steel tubing, which is used to construct brake lines, is prone to rust and wear. Brake fluid will start to leak if rust or corrosion causes a small hole to develop. A spongy pedal results from hydraulic pressure being lost as fluid leaks out and air gets into the system.

A bad master cylinder

There are seals all over your master cylinder that keep everything functioning as it should, despite the fact that your brake lines can rust and leak. Depending on where the leak is, one of two things can happen if the master cylinder seal is broken.

To start with, spongy brakes can result from braking fluid leaking out of the cylinder. Next, air will enter the system if the leak is in a location other than where the brake fluid normally sits, such as the cap.

As a result of both the deterioration of the braking fluid and the problems that this air can cause, the brakes will become spongy. To prevent the issue from reemerging shortly, you must fix the leak and flush the brake fluid.

Contaminated or old brake fluid

The oil in your engine and other mechanical components in your car is similar to the brake fluid. It is advised to replace your brake fluid no less frequently than every two years.

If the fluid is not changed for an extended period of time, it may actually absorb moisture from the air and alter the fluid’s compression properties. Despite the fact that brake fluid has a long lifespan, it does eventually wear out.

Although some manufacturers have established service intervals between 20,000 and 30,000 miles, the reality is a little bit more nuanced. This is because the fluid itself can last over 100,000 miles if the brake system is free of leaks.

Air, however, begins to oxidize and contribute moisture to the fluid as soon as it is introduced to the system. Your brake system will suffer because of this. The brakes will feel softer as more moisture is added, which is a warning sign that you need to flush the system and replace your fluid.

Damaged brake calipers

The area around the brake calipers is another usual location for leaks. The brake pistons contain seals that keep the fluid where it should be, but if those seals begin to degrade, a leak may develop.

Even if it doesn’t happen often, it can be a big issue if it does. Not only will your brakes be spongy, but there won’t be enough brake fluid in the cylinder, and it won’t reach around the rotors and brake pads. If your brake caliper is leaking, you need to have it replaced right away.

Brake Shoes Need Adjustment

You might need to make adjustments to your car’s braking shoes and drums. However, you should keep up with maintenance because, as they wear, it’s normal for some adjustments to be made. Additionally, you should occasionally use the parking brake. This easy action keeps the rear brake shoes adjusted and engaged.

Leaking brake booster

The brake booster is another essential part of your car’s braking system. The force you use when using the brakes is enhanced by the brake booster.

Despite the fact that this is a useful feature, there is a slight possibility that you could end up with what appears to be spongy brakes, but it is still really a drop in brake pressure as you press the pedal.

A malfunctioning ABS hydraulic assembly

If ABS is installed in your car, a hydraulic unit known as the ABS modulator is also present. There are numerous valves and solenoids that could malfunction in this assembly.

The valves may not open properly if the ABS control module experiences an internal failure, which would result in a spongy pedal. Additionally, this could interfere with the ABS.

Failing wheel cylinders

The drum will rotate against the wheel if you have a drum brake system. Brake shoes in the drum are pushed into the drum by the pistons in the wheel cylinder.

To move the shoes into the drum and slow the wheels down, hydraulic pressure is required. However, corrosion in the wheel cylinder might result in fluid leaks, which lower the pressure. All that is left is a soft brake pedal.

Read more: Brake pad and rotor replacement cost

Signs that your car’s brake pedal is spongy or soft

The pedal sinking more than it should is the most obvious sign that the brakes have become spongy. The pedal should continue to exert an appropriate amount of pressure in a properly functioning braking system.

When you push down on the brakes, you should be aware of where the pedal typically presses. The first sign that they are becoming spongy or soft is if the pedal begins to fall lower than usual.

By taking note of this sign as soon as possible, you can prevent larger issues. You might have to rely on the warning system to alert you to a problem if you’re not used to the car or haven’t detected any problems with the pedal.

Modern vehicles come equipped with dashboard warnings that automatically activate when a failure occurs. You could see a brake warning light on your dashboard.

This does not necessarily imply that the brake pedal is spongy, though. It can be a sign of any braking system issues. In any case, it shouldn’t be disregarded.

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Is it safe to drive with a spongy or soft brake pedal?

No. Your car is unsafe to drive if your brake pedal feels spongy. Find the root of the problem as soon as you can, then fix it. Any car can experience spongy brakes, which are a common and dangerous issue as well as a sign of more serious issues.

Most significantly, a spongy or soft brake affects how fast a vehicle can stop. A small leak can become a big one with just a push of the brakes, so spongy brakes may be a sign of one. If a leak turns into a blowout, all brake pressure will be lost.

Read more: Understanding Car wheel parts

How to fix a spongy or soft brake pedal

For one to fix a spongy or soft brake pedal, one must first identify the main reason for the problem. You must check for and fix any brake fluid leaks in order to fix a soft or spongy brake pedal.

How to fix a spongy or soft brake pedal

It’s critical that the brake pedal be completely closed because even pinhole leaks can make it spongy or soft. If not, the issue needs to be resolved by replacing the faulty parts. Additionally, you should bleed the brakes and check that the brake shoes are adjusted correctly.

After that, you should check components like the brake master cylinder and other braking components. The procedure is simple if your diagnosis shows that the brakes need to be bled.

If the manufacturer doesn’t advise something else, you can follow these basic guidelines:

  • Park the car on a level spot. Lift the vehicle, then place it safely on jack stands.
  • Remove the master cylinder’s cap and use a vacuum pump or a turkey baster to drain the old fluid. Don’t let the master cylinder become fully dry.
  • Fill the master cylinder with new brake fluid. Keep the cap open to allow for airflow. To figure out which wheel needs to be bled first, check the service manual.
  • You must complete the steps in a specific order, starting with the wheel that is farthest away from the master cylinder.
  • To bleed the brakes, locate the valve. On drum brakes and the wheel cylinders of disc brakes, this small screw is normally located on the brake caliper.
  • A seal will form when your vacuum pump is connected to the bleeder valve. Use a wrench to open the valve.
  • Empty the old fluid with a vacuum pump.
    Make sure the master cylinder hasn’t gone dry as the fluid bleeds out of the valve by checking it as it happens.
  • Continue filling the master cylinder with new fluid.
    When there are no longer any bubbles and the liquid turns clear, you can stop.
  • After closing the valve, proceed with the other wheels. When you’re done, you need to confirm that the master cylinder is fully filled. Reinstall the cap.
    Lower the car back to the ground with care.
  • Test-drive your car to see whether the brakes feel better. They ought to no longer feel spongy but rather firm.

Other things to do in order to fix a spongy or soft brake pedal

Before you refill the system if the low fluid is the result of a leak, the necessary hoses need to be replaced. Any more defective components must also be replaced.

Whether the issue is with a bad master cylinder or faulty calipers, your diagnostics ought to have helped you identify the issue.

If you can perform the repair yourself, adhere to the steps outlined in the service manual. You should seek assistance from a professional if you face any problems or if you don’t feel qualified to handle them.

Even though some of these steps appear straightforward, it is never a good idea to do something you are unfamiliar with.

Your on-road safety depends on your brake system. You should therefore refrain from tampering with anything you lack the necessary experience for.

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How do you fix a spongy brake pedal?

Consider replacing or cleaning the brake fluid if you detect soft or spongy brakes. Removing air from the brake system by flushing brake fluid is also known as “bleeding the brakes.” Air can get trapped in a system if it is not thoroughly bled after replacing a component. Over time, brake fluid can collect moisture.

Can a bad brake caliper cause a soft pedal?

There is an internal or external leak in the brake master cylinder. The brake master cylinder is not the only place where the system has a leak. A frozen or rusty moving part in one or more of the calipers prevents it from moving as it should.

How do I know if there’s air in my brake lines?

  • Spongy brake pedal The brake pedal will feel spongy when you press it, which is one of the most obvious signs that there is air in the brake lines.
  • Loose brake pedal
  • Ineffective brakes.

What are the symptoms of a failing master cylinder?

The pedal will be impacted if it malfunctions since the cylinder won’t distribute pressure effectively. It will wear out and begin to leak if you keep driving your car with a damaged cylinder. When pressed, the pedal may sink quite a bit and feel mushy and spongy.

What is the most common cause of a spongy brake pedal?

A soft or spongy brake pedal is most frequently caused by air in the brake line(s). The brake pedal may feel soft or spongy if air gets into the brake lines and prevents the brake fluid from flowing properly.

How do you test a brake master cylinder?

The rear master cylinder plunger can be pressed and held in place with a screwdriver. Past a few millimeters, the plunger ought to be quite firm, if not immovable. A problem with at least one of the internal seals is present if the plunger keeps moving in.

Why is my brake pedal soft after bleeding?

If you pump the pedal and it goes firm but slowly releases while you hold it, you can have another leak or a faulty master cylinder. Normal use can cause brake fluid to become contaminated and internal master cylinder wear, but only for the time it takes for your brake pedal to completely deteriorate.

What would be the cause of a dropping brake pedal with no fluid loss from the system?

The most likely reason for a sinking pedal in the absence of an external leak is an internally leaking brake master cylinder. We might think about boiling fluid because of moisture contamination or friction material gassing if the brakes were hot.

Why are my brakes not building pressure?

This could be caused by a number of issues, including a brake line leak, a failing seal in the master cylinder, or air being introduced into the braking system. Your initial response should be to quickly press the brake pedal with your foot when you encounter spongy brakes.

Can a booster cause a soft pedal?

When you press the brake pedal, the brake booster helps the braking system by giving it power. Your brakes may not engage when you press the pedal if the system is failing, resulting in either a soft pedal or a pedal that doesn’t appear to work.

That is all for this article, where we discussed the most common causes for a spongy or soft brake pedal, whether it is safe to drive with a spongy or soft brake pedal, and how to fix the problem.

I hope you learn a lot from reading this article. If you do, kindly share it with others. Thanks for reading; see you around!