Why Does My Brakes Hissing When Pressing Brake Pedal?

The reason for this is that there’s a vacuum inside the brake fluid reservoir, and when you press the pedal, you’ll release air into the reservoir. This air will cause bubbles to form in your brake system, which will create a hissing sound as you pump your brakes.

You can fix this problem by bleeding your brakes. Bleeding your brakes allows you to remove any air from your system so that no bubbles will occur when you press on the pedal.

Remove the cap from your master cylinder reservoir and set it aside. Loosen the bleeder valve on top of it with an Allen wrench or a socket wrench and let all air out of the reservoir until no more comes out of it.

Replace the bleeder valve cap with a new one and tighten it back down securely on top of it again so no more air can escape into your system during this process. You may need someone else’s help here if you’re working alone because there may be some resistance from the force-feeding fluid through those small openings where they connect to each other.

How does the brake system work?


These are the actual pads or shoes that press against the rotors or drums to slow down or stop your car. They come in many forms hydraulic, cable-operated, and disc brakes are just a few examples.

Hydraulic brakes rely on fluid pressure to move pistons inside cylinders, while cable-operated systems use cables to transmit force from the pedal through levers and linkages until they reach the brake pads or shoes themselves.

Rotors Drums

These are the spinning discs or drums that your brake pads or shoes press against when you step on your pedal. Rotors can be either metal discs with grooves cut into them or solid metal rings.

Drums are similar but have holes cut into them instead of grooves; these holes allow for better cooling through convection currents created by air flowing past them when wheels spin faster than any other part of the vehicle.

What can cause a brake hissing noise?

The most common reason for brake hissing is simply the presence of moisture in the brake system. Moisture can condense inside your vehicle’s braking system when it’s cold outside and then turn into ice when it gets warmer.

Water will freeze at 32 degrees Fahrenheit, but if your brakes are designed to be used at much higher temperatures than that, they won’t have time to thaw before they’re activated and begin cooling down again.

Another possibility is that air has entered your brake lines through cracks or holes in their hoses. If you suspect this is the problem, you can try to find leaks by spraying soapy water on all of your hoses and watching for bubbles where they connect to each other or their fittings.

If neither of these causes seems likely, then it might be time to take your car to a mechanic who can diagnose exactly what’s causing the noises and recommend fixes accordingly.

What’s wrong with my brakes?

The brake pads are worn down. This causes the brake pad to rub against the rotor. The brake fluid level is too low. The fluid helps to cool and lubricate the brakes. If it’s low, you may hear a squealing or grinding sound as you press on the pedal.

Brake fluid leaks from the master cylinder or other part of your braking system. You may hear a squealing or grinding sound when brakes are pressed.

How to stop or prevent the brakes from hissing?

Check your brake fluid levels regularly and add more if needed (you may need to top up with fresh fluid every few months. This will ensure that there is plenty of fluid available for proper braking.

If your vehicle has been sitting idle for some time without being driven, it may be advisable to bleed the brakes before driving again. This is especially important if you have recently replaced your brake pads or rotors and need to ensure that all air has been removed from the brake system so they can work properly again when engaged.

How to fix the brake hissing problem?

The most likely cause of brake hissing is that some of the pads have worn down. If this is the case, you’ll need to replace the pad that’s worn out. The other possibility is that there’s something wrong with your brake fluid, which could be due to contamination or lack of maintenance. If this is the case, you’ll need to flush your brakes and replace their fluid.

What is the cause of this noise?

There is air escaping from your brake system. The brake pedal has a master cylinder that acts as a reservoir for hydraulic fluid. When you press the pedal, hydraulic fluid is pumped into the brake lines and distributed throughout the brakes. When you release the pedal, it sucks air back into the master cylinder.

The reason you hear this hissing noise is because when you press on your brake pedal, you are pushing out more air than when you release it. So if you hear a hissing noise when pressing on your brakes, it’s likely that your braking system needs to be bled.


The brakes are one of the most important parts of a car. They allow you to stop safely and quickly, and they’re what keep you from getting into an accident. If you find that your brakes are hissing when you press the pedal, it’s time to take them in to get fixed. You’ll be able to drive safely again, and you won’t have to worry about getting into an accident.

Steven Hatman
Steven Hatman

We break down every information into easy-to-understand articles that cover all the categories anyone who owns a car needs to know about, such as oil , brakes , tires and etc. Our car guide is free and updated regularly for you to use as a resource, not only when you have an issue with your car but even before buying a new or used car! We also give tips on what to look for in each category or part of your vehicle.