Air Noise When Pressing Brake Pedal

If you hear air noise when pressing brake pedal, it could mean that the serpentine belt of the car is damaged. You might have to repair it immediately. Learn more about this problem in the article below.

If a vacuum hose all-around the engine is detached or if a vehicle’s serpentine belt is damaged, you may experience a hissing noise. However, if you hear air noise when pressing the brake pedal, it’s likely the brake booster is losing air, which could indicate a leak inside the booster diaphragm, vacuum hose, or master cylinder gasket.

Let’s dig deeper into the matter and gather more information related to it.

Air Noise When Pressing Brake Pedal

The brake booster works by utilizing vacuum pressure. A diaphragm within the brake booster controls the pressure while the brake pedal isn’t depressed. A rod travels into the master cylinder and brake booster when the pedal is depressed. This phase generates vacuum pressure solely on a single side of the diaphragm to support stopping power.


Air Noise When Pressing Brake Pedal


A hissing noise could result if anything goes wrong with that process. The following could be the cause:

  • A vacuum hose hole is used in combination with the brake booster.
  • A fault causes the malfunctioning of the brake booster with the booster diaphragm.
  • A leak of air into the brake booster from the master cylinder gasket.
  • A foam silencer that is missing or damaged. You may hear a hissing sound if the foam is absent or broken. A piece of foam that covers the hissing sound is included in many automobiles with brake boosters.

Common Causes Of Brake Booster Failure

When you apply the brakes, it may appear that air is escaping, but the air is being drawn in in actuality. The noise is usually caused by leaking in the brake booster. On one side of a brake booster, a diaphragm traps the vacuum produced by the engine.

The brake booster has a line that connects to the engine’s intake manifold. Because of the suction created by the engine, pushing the brake pedal is easier, and you don’t need to apply extra force to stop it.

When you hear air noise when pressing the brake pedal, check the brake fluid to ensure you aren’t losing any. Most of the time, no braking fluid is lost.

Air is sucked in through a damaged brake booster O-ring, silencing foam, or diaphragm, causing the noise. When you push the brake or throttle pedal, you may find that the sound goes away in some circumstances.

This issue can be rectified by replacing the brake booster. Because replacing the brake booster involves some DIY abilities, take your automobile to a repair if you do not even plan on fixing the hissing sounds yourself.

Right behind the master cylinder is the brake booster. Between the firewall and master cylinder is the black circular tank.

The hissing sound originating from under the brake pedal area should not be overlooked. If you ignore it any longer, you risk losing your brakes while driving, which may be fatal.


Air Noise When Pressing Brake Pedal


What You Can Do About A Hissing Noise?

If the hissing noise appears to be related to braking, don’t ignore it and hope that it goes away on its own. Because your car’s brake system is complicated, it’s best to bring it to your local firestone complete auto care, where one of our specialists can perform a diagnosis and prescribe any required repairs.

Our professionals can evaluate whether the hissing is caused by anything as simple as a lost or damaged piece of foam or something more severe, such as a brake booster that requires repair or replacement.

Because the brakes are one of your car’s most vital safety features, it’s never a good idea to put off taking care of a problem with them. Taking care of your brakes will allow you to take better care of yourself and the passengers in the long run.

You should obtain routine brake maintenance before a hissing noise develops a problem with your car’s brakes. The cost of assuring your brakes are in good operating order could be pretty high! According to a poll conducted by the research firm IMR, at least one-third of drivers wait until their brakes fail before seeking service.

Frequently Asked Questions

#1. What causes the brake pedal to whoosh?

Air is sucked in through a damaged brake diaphragm, silencing foam or booster O-ring causing the noise. When you push the brake or throttle pedal, you may find that the sound goes away in some circumstances. This issue can be rectified by replacing the brake booster, which you can locate near the main cylinder.

#2. When you press the brakes, should there be an air sound?

When the brake is pressed, the vacuum on the side of the pedal is let out, giving you a vacuum-assist. The noise you’re hearing is that same vacuum being let off, generally muffled by several mufflers and silencers applied to the brake.


Air Noise When Pressing Brake Pedal


#3. My brake booster is making a hissing noise, how shall I fix it?

Replacing the vacuum booster with a new one is a good idea. Pull the master cylinder off by separating the two bolts that hold it in place. Then separate the brake pedal’s pushrod. The olts that hold the vacuum booster to the firewall must be removed.

#4. What does air in brake lines sound like?

The brake booster often makes a whooshing sound when stepping on the brake pedal. A minor leak may generate a sound when you push or release the brake pedal. The vacuum line, booster diaphragm, or master cylinder could be leaking.

#5. Why does a car sound like it’s leaking air?

A faulty exhaust system is the most suitable cause. There’s a lot of noise when your car’s exhaust is leaking. This is because the exhaust system retains and muffles the engine noise. If the problem isn’t a leak, it could be a problem with your transmission not moving in the proper gear.

#6. If there is air in the brake lines, will it be safe to drive?

When you drive, brake fluid stops the brake pedal from inserting. The pedal will gradually migrate closer to the board if air gets into the brake line. When you press the brake pedal, it becomes spongy or squishy. A squishy brake pedal may fail, putting you in danger of an accident.

A Few Final Words

Thank you for reading, we hope we have covered everything that you needed to know about the peculiar air noise that comes when you are pressing your brake pedals. You might also like to read about: Brake Pedal Makes Noise When Released and Brake Pedal Pushes Back When Stopping

Photo of author

Sean Mendez

Hi, I am Sean, a self-confessed petrolhead. I live in Boise, Idaho with a busy family of four and our energetic Labrador retriever. Thank you for visiting my website. You can find my email on the contact page.

Leave a Comment