Audi Quattro Hissing noise when brake pedal is depressed Inspection at your home or office.

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Hissing noise when brake pedal is depressed Inspection Service

How much does a Hissing noise when brake pedal is depressed Inspection cost?

On average, the cost for a Audi Quattro Hissing noise when brake pedal is depressed Inspection is $95 with $0 for parts and $95 for labor. Prices may vary depending on your location.

CarServiceEstimateShop/Dealer Price
1986 Audi QuattroL5-2.2L TurboService typeHissing noise when brake pedal is depressed InspectionEstimate$114.99Shop/Dealer Price$132.49 - $145.62
1983 Audi QuattroL5-2.2L TurboService typeHissing noise when brake pedal is depressed InspectionEstimate$94.99Shop/Dealer Price$112.52 - $125.67
1985 Audi QuattroL5-2.2L TurboService typeHissing noise when brake pedal is depressed InspectionEstimate$94.99Shop/Dealer Price$112.52 - $125.67
1984 Audi QuattroL5-2.2L TurboService typeHissing noise when brake pedal is depressed InspectionEstimate$94.99Shop/Dealer Price$112.48 - $125.60
Show example Audi Quattro Hissing noise when brake pedal is depressed Inspection prices

Brakes are the most important safety components on your vehicle. Despite that importance, it’s easy to take them for granted, at least until your car begins to do strange things. Ordinarily, pressing your brake pedal should result in only the car slowing down or stopping. If you hear a hissing noise when the brake pedal is depressed, it may mean there’s something that needs to be repaired in the system.

How this system works:

On many cars, the master cylinder works in tandem with a brake booster. The brake booster is mounted to the firewall, generally in front of the steering wheel position, and the master cylinder attaches to it. The entire point of the brake booster is to make it easier to press the brake pedal and slow or stop the car.

Your brake booster works on vacuum pressure. There’s a diaphragm inside that is responsible for maintaining pressure when you’re not pressing the pedal. However, when you do press the pedal, a push rod moves forward within the booster and into the master cylinder. The side of the diaphragm facing the cabin vents to atmospheric pressure, while vacuum is maintained on the other side.

This then equalizes with pressure on the other side of the diaphragm, providing the boost needed to make pressing your brake pedal easier. The hissing noise you hear when the brake pedal is depressed could be nothing more than ordinary operation, or it could be a sign of a deeper problem. There are a couple of different potential issues here, some more severe than others.

Common reasons for this to happen:

  • Leaking Vacuum Line: Your brake booster is supplied with vacuum from the engine via a vacuum hose. It’s usually located near the firewall. If this hose has a leak, it can be heard within the cabin.

  • Leaking Brake Booster Diaphragm: The diaphragm that’s responsible for maintaining pressure within the brake booster can fail, particularly if the master cylinder is leaking fluid into the booster. When this happens, you’ll hear a hissing sound when depressing the brake pedal, but the pedal itself will be much, much harder.

  • Damaged or Missing Foam Silence: Most cars equipped with brake boosters also have a foam silencer that’s designed to help prevent you from hearing that hissing sound. If the silencer has degraded or been damaged, you’ll hear the hissing sound.

  • Failing Master Cylinder: If you hear a hissing sound and suspect that the problem is the diaphragm in the booster, the actual cause is likely the master cylinder beginning to fail. Signs that the master cylinder is leaking into the brake booster include low fluid in the reservoir with no visible leaks.

What to expect:

A top-rated mobile mechanic will come to your home or office to inspect your brake system, including the brake pedal operation, the brake booster and listen to the hissing sound. The mechanic will then provide a detailed inspection report that includes the scope and cost of the necessary repairs.

How it's done:

The mechanic will need to crank the car in order to verify the hissing sound, and a test drive may be necessary to duplicate the complaint. Additionally, the mechanic will inspect the brake pedal operation, the condition of the brake booster, the master cylinder, the level of fluid in your system and more.

How important is this service?

Power brakes are wonderful things, making it far easier to work a brake pedal that would otherwise require significant force to activate. While the hissing sound may be a sign of nothing more dangerous than a failed piece of foam, it could be a symptom of something much more worrisome – a damaged brake booster and a failing master cylinder. You cannot afford to take chances with your brake system. One of our professional mechanics can inspect the entire system and determine if there’s cause for concern, and what needs to be done if there is a problem.

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Danny

11 years of experience
269 reviews
Danny
11 years of experience
Audi A4 Quattro L4-1.8L Turbo - Bleed Brakes - Philadelphia, Pennsylvania
He knows what he’s doing thank you Danny quick and efficiently solving and correcting my issue

Tien

23 years of experience
903 reviews
Tien
23 years of experience
Audi A4 Quattro L4-2.0L Turbo - Oil Change - Oakland, California
Tien changed my oil and filter. He was competent, and I appreciate him working on my car. Somethings that could improve are professionalism and cleanliness. Tien was smoking a cigaret the whole time he worked on my car. That seemed a bit unsafe because we were working near the engine compartments and oil. He also spilled about a quart of used engine oil on the street that we were working on, and didn’t have enough supplies to clean up the spill. Based on these two things, I can not say this was a good oil change experience.

Michael

11 years of experience
17 reviews
Michael
11 years of experience
Audi S5 V6-3.0L Turbo - Brake Pads Replacement (Rear) - Riverside, California
Great service technician!

Chris

20 years of experience
448 reviews
Chris
20 years of experience
Audi A3 L4-2.0L Turbo - Brake Pads Replacement (Rear) - Portland, Oregon
It's a pleasure working with Chris who is always early or on time and provides 5 Star customer service.

Excellent Rating

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2,221
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