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The 2021 Guide To Spongy Brakes (Causes + Solutions)

March 25, 2021

Looking for solutions to spongy brakes?

Your brake pedal should feel firm when you press down on it. 

If it feels soft and spongy, something is wrong

And since brakes are a vital part of controlling your vehicle, you should immediately get your vehicle checked to diagnose the issue.

In this article, we’ll discuss the symptoms and causes of a spongy brake pedal. We’ll also highlight how you can keep your brakes in perfect condition.

This Article Contains:

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Let’s dive in.

How Does Your Brake Pedal Work?

The firmness of your brake pedal is a result of the brake fluid pressure in your brake system’s master cylinder and brake lines. 

When you press down on your brake pedal to slow or stop your car, the master cylinder responds by pushing brake fluid into the brake lines to activate the brake piston. The caliper piston then closes on the rotor and squeezes the brake pad

If your car uses drum brakes, an actuator is activated in response to brake pedal pressure. This pushes the shoes outward against the inner surface of the drum to slow your car down.

Essentially, irrespective of which type of brake system you use, the entire process starts with you pressing down on your brake pedal.

What Are Spongy Brakes?

In a normally operating brake system, you should feel little to no difference in the firmness of the brake pedal during any part of the braking process. 

However, there are several reasons that could lead to a spongy or soft pedal.

If you press down on a spongy brake, here’s what happens: Instead of all the pressure going to the brake pistons, some of it leaks out.

When releasing the brake pedal, the returning motion sucks in air, and you experience a pedal that goes directly to the floor with minimal resistance.

The 3 Symptoms Of Spongy Brakes

Spongy brakes can compromise your vehicle’s performance, and more importantly, they can compromise your road safety. 

Here are a few noticeable things that can warn you of spongy brakes:

1. Your Brake Pedal Keeps Sinking

If a vehicle is unable to hold brake pressure as effectively as it should, it’ll result in your brake pedal sinking with no resistance whenever you press down on it.

If your brake pedals are sinking, it’s a tell-tale sign that your brake system has some issues, and you need to get it inspected as soon as possible.

A short-term solution to slow your car down with such a pedal is to repeatedly pump your brakes since pressing down just once won’t generate enough pressure.

2. Your Brake Warning Lights Are On

Some cars have a built-in dashboard indicator light that lights up when the brake system is compromised.

Your warning light could be notifying you of anything – from an engaged parking brake to the car running low on brake fluid. 

However, it could also indicate problems with your brake fluid pressure.

To be safe, consider having all your brake components checked whenever the warning light flashes.

3. Your Pedal Requires Pumping To Keep It From Creeping Ahead

If you need to repeatedly pump your brakes to slow your car down, check your brake system for a fluid leak.  

If the brake warning light is not on and there are no visible brake fluid leaks, your master cylinder may be worn or leaking internally. 

It’s a sign that you need to take your car to a mechanic immediately.

10 Common Causes Of Spongy Brakes

Your braking systems rely on evenly distributed hydraulic pressure to bring your vehicle to a stop. Any disturbance in the balance of pressure will result in your car needing more time, distance, or effort to stop itself.

Here’s what could cause these pressure imbalances that lead to spongy brakes: 

1. Air In The Brake Line

When the brake fluid is low, air gets into the brake line to fill the void.

An air bubble can prevent the brake fluid from flowing properly and compromise the hydraulic pressure of your brake system. Your brake fluids can also absorb moisture overtime if your bleeder valve is loose. 

The mechanic will help you flush the brakes (commonly called brake bleeding) to: 

2. Low Brake Fluid

Brake fluid plays a key role in helping your car slow down.

How?

Brake fluid converts the pressure you apply on the brakes into the force required to bring your car to a stop.

Low brake fluid will disturb the hydraulic system of your brakes and make your brake pedals sink to the floor.

3. Damaged or Leaking Brake Line

Since brake lines are usually made of steel tubing, they can rust from:

This can result in a brake fluid leak, which leads to low hydraulic brake fluid. This, in turn, can affect your pedal travel as it’ll require repeated pumping to generate the right amount of pressure. 

4. Brake Caliper Damage

Brake calipers clamp your brake pads against the rotor to slow or stop the vehicle.

Braking relies on friction – which creates a great deal of heat. This heat can damage your car’s disc brake caliper over time. 

They can also become corroded with rust if they catch moisture.

Some common signs of caliper damage include:

If the brake caliper is damaged, it could leak which will affect your brake fluid pressure.

5. Worn Master Cylinder

The master cylinder is a key element of your car’s braking system.

It holds the brake fluid, generates hydraulic pressure, and feeds it to the front and rear brakes. It essentially pushes the brake fluid where it needs to be to help bring your car to a stop. 

Over time, seals within the cylinder can break or leak. And since the master cylinder is responsible for generating hydraulic pressure, any damage to it can greatly affect your brake fluid pressure. 

6. Leaking Wheel Cylinder

Some cars come equipped with disc brakes on the front wheels and drum brakes on the rear wheels. 

Drum brake systems feature a drum that rotates along with the wheel. 

Inside the drum is a set of brake shoes that are pressed against the drum by the wheel cylinder to slow down the wheel.

Corrosion in the brake cylinder can cause brake fluids to leak and result in a loss of hydraulic pressure, making your brake pedal feel soft. 

7. ABS Modulator Issues

Vehicles equipped with an Anti-lock Braking System (ABS) have a hydraulic assembly called an ABS modulator. It’s responsible for optimizing the brake pressure delivered to each wheel.


Any damage to the modulator can cause a brake valve not to operate properly, resulting in a spongy pedal.

8. Misaligned Rear Brake Shoes 

Drum brakes have a self-adjuster that maintains a minimum gap between the brake shoes and the drum. When the lining of the brake shoe is worn out, the gap between the drum and brake shoe increases, and the adjuster adjusts itself to maintain the minimum gap.

If your vehicle has a rear brake drum and pumping the brake pedal improves your brake pedal feel, your rear brake shoes may be out of adjustment. 

9. Faulty Brake Booster

You may also experience a spongy pedal if you use power brakes and your brake booster fails.

Why?

When a brake booster fails, it’s not able to give you the braking assistance it is supposed to. 

This usually happens when the brake booster is full of fluid, hampering its abilities. 

How To Fix A Spongy Brake Pedal

If you experience any of the symptoms we mentioned earlier, get your brakes inspected by a mechanic immediately. 

However, if you’re already on the road and suddenly experience spongy brakes, rapidly pump the brake pedal with your foot.

Why?

Soft brakes arise because your vehicle’s brake master cylinder isn’t able to generate the pressure required for efficient braking. Pumping the brake pedal should generate enough pressure to stop the vehicle on the side of the road safely.

DIY Brake Repairs: Are They Possible?

While you can try to fix spongy brakes on your own, it’s recommended that you leave the job to an experienced mechanic.

Why?

Brakes are highly crucial to vehicle safety. 

It’s always safer to trust in the expertise of a professional to do it for you. They can diagnose any leaks in your brake system and bleed your brakes for you with specialized equipment.

The Easiest Way To Keep Your Brakes In Perfect Condition

If you sense that something is wrong with your brakes, you can contact a professional mechanic to help you.

When you’re hiring a mechanic, verify that they:

Fortunately, there is a super-easy way to find a mechanic that fits all these criteria:

RepairSmith is the most convenient car repair and maintenance solution.

When you turn to RepairSmith for your brake repairs, you can:

Fill out this online form for a free quote on how much your repair could cost.

Wrapping Up

There are a number of reasons why you could be experiencing a spongy brake pedal. 

If you experience any of the symptoms we mentioned, be sure to have your vehicle immediately inspected by your trusted mechanic.

Luckily, with RepairSmith, you can get a brake inspection done with a qualified technician- right in your driveway! 

So don’t wait. 

Schedule an appointment with RepairSmith to have your soft brake pedal inspected as soon as possible.