S3 AMK servo valve question

[TurboLover]

Hello. I have s3 8l amk engine. Today when i was looking under the hood i saw something really strange that bothers me.
In the picture is this one way valve for the servo? What does it do? Also as the way it looks i think it's doesn't work, right?
Where can i get a replacement? And i saw a picture in this forum where someone has removed this valve.
Can the car/brakes work without it?
Sorry for my English.

 

[<tuffty/>]

Looks like the EVAP check valve... I assume this pipe goes into the top of the throttle body?

<tuffty/>

 

[TurboLover]

Yes. It goes there.

 

[<tuffty/>]

Its EVAP then... nothing to do with the brake servo... removing it however will through a fault code (incorrect flow N80) so needs coding out of the map to do an EVAP delete..

There is nothing really to gain from removing so leave it be unless you really feel it needs to go

<tuffty/>

 

[TurboLover]

Ok. Thank you. I have another worry this time with brakes and servo for sure i think. My brakes are ***t. The travel of the brake pedal is almost the half to the floor. After the first half it starts to stop, but nothing that i was expecting for a "sport" car with 200 bhp. Also when i press the pedal it's hissing. Do i have leak somewhere around the brake pedal or it's normal (i doubt)? The car came with good disks and pads. I think that the brakes need bleeding. But since i don't know how to do it i'm looking for another solutions.