BMW 525iT Hissing noise when brake pedal is depressed Inspection at your home or office.

Our certified mobile mechanics come to you 7 days a week between 7 AM and 9 PM.

Estimate price near me

Service Location

Customer Ratings

(6,729)

How A Diagnostic Works

Instantly book a certified mobile mechanic to come to you

Mechanic diagnoses the problem and quotes necessary repairs

Your vehicle is ready to go

Fair, upfront & transparent pricing for all services

Our certified mobile mechanics can come to you now.

Customer Ratings

(6,729)

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 BMW 525iT 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
1993 BMW 525iTL6-2.5LService typeHissing noise when brake pedal is depressed InspectionEstimate$114.99Shop/Dealer Price$132.49 - $145.62
Show example BMW 525iT 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.

Fast and easy service at your home or office

Backed by 12-month, 12.000-mile guarantee


Meet some of our expert BMW mechanics

Real customer reviews from BMW owners like you.

Excellent Rating

(6,729)

Rating Summary
6,273
206
60
45
145
6,273
206
60
45
145

Victor

35 years of experience
229 reviews
Victor
35 years of experience
BMW 325Ci L6-2.5L - Car Battery Replacement - Albuquerque, New Mexico
Very professional and competent!

Marco

29 years of experience
229 reviews
Marco
29 years of experience
BMW 330i L6-3.0L - Headlights do not change from low to high beam - Rancho Cucamonga, California
Marco was professional, courteous, with great attitude. Will judge his work performance later. So far so good .

Khoa

20 years of experience
402 reviews
Khoa
20 years of experience
BMW Z3 L4-1.9L - Camshaft Position Sensor - San Jose, California
He was very professional, knowledgeable and kind. I will be recommending him to my friends.

Brian

23 years of experience
681 reviews
Brian
23 years of experience
BMW 750Li V8-4.8L - Check Engine Light is on - Jacksonville, Florida
He was very knowledgeable. And I like that he was very honest.

Excellent Rating

(6,729)

Rating Summary
6,273
206
60
45
145
6,273
206
60
45
145
Number of BMW services completed
74019+
services done by our mechanics
TOTAL NUMBER OF EXPERT BMW MECHANICS
1100+
experts on our platform

Recent articles & questions

The Best Used Cars to Buy If You Love Road Trips
If If you love to travel, comfort is very important in a vehicle. You want a nice, quiet ride, comfortable seating, and enough room. We have evaluated several used vehicles, and narrowed our favorite road trip vehicles down to the...
P0216 OBD-II Trouble Code: Injection Timing Control Circuit Malfunction
P0216 P0216 code definition Injection timing control circuit malfunction What the P0215 code means The P0215 code means that the vehicle’s powertrain control module has detected a fault in the fuel injection timing control system. The powertrain control module takes...
What are the Car Pool Rules in Idaho?
Idaho Idaho is a beautiful and rural state, and as a result its scenic drives (https://www.yourmechanic.com/article/top-10-scenic-drives-in-idaho) are much better known than its freeways. However, as with all states, freeways are responsible for getting a large number of Idaho citizens to...

Suffering a battery drain.

When there is an electrical draw that drains your car’s battery, it is known as a parasitic draw. A parasitic draw or drain is usually first noticed when the battery is discovered dead after the vehicle has been off with...

Air conditioning compressor stopped working

If the compressor was recently replaced and has stopped working then most of the time it is because a fitting was left loose and all of the refrigerant came out or there is a loose electrical connection. It is also...

EMERGENCY SOS

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (844) 997-3624 · hi@yourmechanic.com