Vacuum leak

Black Pearl

Registered User
Dec 8, 2017
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Evening all,

I have just bought myself a 2010 S4 and I love it!!!! I have a slight issue already though. I have a hissing noise coming from the drivers footwell. When I press on the brake the noise goes away. I have tried looking for a connection or a hose but I have had no luck. Does anyone have any idea what this could be or have a diagram of that area? I have a left hand drive car, not sure if this makes a difference.



Here is a picture of the beast with a bow on it.


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Hello and welcome to this forum!

Definitely that bow is causing problems, these cars do not like being dressed up!

In other words I have not got an answer for you, my 2011 S4 still works okay - sorry!
Thank you!!

I wanted to keep it but the dealership said no. These cars are amazing!!
Great car, good choice!

Sounds like a brake booster vacuum leak, over time as it gets worse you will need to put more effort into the brakes to get them to perform.

Could be a loose vac line or worst case a leak on the diaphragm.

Had it on our S3, glad I got a garage to repair as it needed rectifying from the engine bay side which was a touch on the tight side! The S4 I would imagine will be the same!

Great car and hopefully you will get it back soon!

I'll check the lines out again but I'm thinking it is the brake booster too.

Yeah there isn't much room under there i think it might be a tight squeeze.
I had the same on my A4 replaced the Brake servo/Booster and its been alright since. I done the job on my drive its not a bad job. You will need the special tool to detach the brake pedal from the servo. I had to order the tool from the US so you shouldn't have any problems getting hold of it.
Surely the car has some warrenty from dealer? Also you have plenty of comsuner rights in first 6 months to get em to fix it for free.

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No they didn't have any warranty. I could of paid $3500 for extended warranty but stuff that!! I will try and get it fixed for free if not at least discounted.