Hissing noise when applying brakes

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First, we'll review the common causes of hissing noise when applying brakes, such as a brake fluid leak, damaged brake lines, or a faulty brake booster. We'll also discuss the symptoms and effects of the hissing noise, including decreased braking performance, longer stopping distances, and potential safety risks.

Next, we'll guide you through diagnosing the cause of the hissing noise, including how to inspect the brake lines and booster and check the brake fluid level.

We'll also provide tips on how to avoid common mistakes when diagnosing the hissing noise, such as overlooking small leaks or not properly checking the brake booster.

Finally, we'll discuss what steps to take to fix the problem, including how to perform any necessary repairs or replacements and properly bleed the brake system.

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[razzis]

This is because of leakage through the break booster plunger seal. Most probably you'll have to change the entire booster as the seal is not available is market. Else it's just because of that tiny rubber seal going bad.

Practically replacement of that seal doesn't worth/cost more than 2 $ but since company don't provide repair kits anymore it's sad that the whole booster needs to changes even if it's in good shape.

[spike]

I have the same thing but only when stepping the brake pedal.. how did you fix it?

[palerider]

I have a car that has the whooshing sound when I depress the pedal fast but not when a moderate press. It passes vacuum test. I think there's a seal where ambient air passes through to back fill the diaphragm on the non vacuum side when the pedal is depressed and vacuum hits the diaphragm and moves it with the pedal. I have good stopping power so I think Ill look under the dash for the seal problem. Probably have to change the booster to stop it but doubt the system isn't safe just annoying sound. It's an old car I am worried the replacement will not be as good as what I have probably a refurbished part.

[hendricks]

I got a 91 Ford F350 and my brake pedal goes all the way down to the floor with truck is off and on. And seems there is no pressure. Is it the brake booster or master cylinder. Please help. I almost crashed yesterday with no brakes. I had to drive all the way home with the emergency brake on.

[codyshaw]

Ok fellas. Same whoosh (blow off valve) noise but only when pressing gas.. also does it after turning vehicle off. Any vacuum lines that relay from booster to both pedals?? Sound is comjng from behind pedal seems like.

[gazebowagi]

I have the exact same issue. How can I fix it? Please 🙏 🙏 🙏

[prizzo]

I need some help understanding this thing mine is the same problem

[statikjose]

mines doing this rn only when pressing the brakes started today out of nowhere when i push brakes can hear a whoosh/ air noise until you let it go and while driving if you brake pedal goes to the floor and takes forever to stop the truck

[deananthony]

1993 Buick LeSabre, when I first get into the car and press the break pedal I have a mushy pedal and a woosh sound, afterwards the pedal is firm and I don't get any other sounds from the brakes at all. Should I be concerned or is this just the brakes resetting after car setting for a week or more. I drive so little these days.

[Drago]

Yep deffo the booster, mine the entire filter/ sound deadener was gone.

[papatg]

My car makes this noise and what should I do?

[downjesse]

This happened to my 2000 Escalade and it was the break booster

[zack]

Is this a confirmed issue where the brake booster needs to be replaced? I have the same exact issue and I believe it’s the same model as mine as well. 2004 GMC envoy. Please get back to me idk what to do

[TKD]

I have the opposite problem when I hit the brakes it makes that sound and they go to the floor

[Dyna]

My 81 vette does this what was the problem?

[Be]

You have a leak on air brake pedal cut out.

[princesen]

Only things could be the reason in here.. If the breaking system has no issues then it's just the boot so how to replace the boot some one could ADVISE 🤔 😉 Thanks

[microwavedmetal]

Heard the noise from my moms car while giving our dog their de wormer

[robflange]

Tactically NY AG might go after the Trump plane
Why?, apart from money what's the next best way to slow/stop Trumps electioneering
What happens if seized assets are run Into the ground / bankrupted etc?

[alexeudy]

I’m having the same issue but I just replaced the booster