Hissing Noise From Brake Pedal
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Do you hear a hissing noise coming from the brake pedal? The noise may be constant or only heard when you press the gas pedal.
If you hear a hissing noise from under the dashboard that changes when you press or release the brake pedal area, it most likely is a brake booster that is failing.
Symptoms
- Air Noise from the brake pedal
- Hissing sound when applying the brakes
- The brakes sound like air is coming out.
- The brake booster problem hissing sound
- Whoosh sound when you apply the brakes
Common Cause
Brake Booster
Do you hear a hissing noise when you press and release the brake pedal, even when the car has fully stopped? Does the hissing noise sound like this?
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It may sound like air is coming out when you press the brakes, but the air is being sucked in in reality. A leaking brake booster typically causes the noise. A brake booster has a diaphragm inside on one side of it, the vacuum created by the engine.
The brake booster has a hose connected to the engine’s intake manifold. The vacuum created by the engine makes pressing the brake pedal easier and helps you so that you don’t have to press the brakes as hard to stop it.
Typically, when you hear the hissing noise from the brake pedal, you should check the brake fluid to be sure you are not losing any. In most cases, you don’t lose any brake fluid. The noise is caused by air sucked via a cracked brake booster O-ring, silencing foam, or diaphragm. Sometimes, you may notice that the noise goes away when you press the brake or gas pedal.
Replacing the brake booster will fix this problem. Replacing the brake booster requires DIY skills, so if you don’t plan on fixing the hissing noise, take your car to a mechanic. The brake booster is located right behind the master cylinder. It is the black round tank between the master cylinder and the firewall.
Don’t neglect the hissing sound behind the dash/brake pedal area. If you neglect it, you may lose your brakes while driving, which can be catastrophic.
Brake Pads
Brake pads have a wear sensor. As the pads wear down, the wear sensor contacts the rotor, causing more of a grinding noise when braking. You should only hear this noise when braking, not if the vehicle is stopped.
For more help with your vehicle, check these troubleshooting and repair guides.
