B8 RS4 - what part is this please?

[JohnnyUK]

Hi All

Had this car from new and done just over 60k miles.

Obviously I know every little noise the car makes, but I now have a buzzing at idle that I've traced to this part. If I tickle the throttle the buzz goes away, then returns at idle.

What is this part please?

[InitialDave]

Hmm, looks like a brake servo vacuum pump to me.

[JohnnyUK]

InitialDave said:

Hmm, looks like a brake servo vacuum pump to me.

Oh thanks! Does it matter if it's buzzing a little? Is it a safety concern?

[InitialDave]

Assuming that is indeed what it is, and it's just there to supplement engine vacuum when necessary, my opinion is no, it's probably not a major liability. I would expect the likely failure mode to be lower brake assistance (much heavier pedal) in situations where there's not much engine vacuum.

But I think it's worth asking someone who knows these cars specifically. I'm making some assumptions here.

It also looks like it's quite easy to access and I'd be astounded if it's an RS4 only component rather than covering multiple models (and marques, given this is VAG), so if it's not long for this world, having it replaced might not be too painful.

[JohnnyUK]

OK thank you, I'll get it checked out!