Sucking noise(no pun, really) on start up, mech says........
I did it with the car running, so I could push on the hoses in various places to see if there were any obvious spots. Indeed there were.
If you find the spots, you can use electrical tape as a temporary solution until you replace the hoses (they're fairly cheap).
And no, you don't need to warm up brake lines.....I would change mechanics if somebody told me that.
Here's the pictures, it's almost self explanatory. The pump is driven by a motor in the air box
<img src="http://www.audipages.com/Tech_Articles/enginemechanical/ai1.JPG">
The big diaphrams open up and the pump pumps air into the exhaust
<img src="http://www.audipages.com/Tech_Articles/enginemechanical/ai2.JPG">
There is a small solenoid valve that ports vacuum to the top of the big diaphrams
<img src="http://www.audipages.com/Tech_Articles/enginemechanical/ai3.JPG">
The ross-tech tool can test the component, and I've tested them before, and the air pump is quite loud, probably it.







