2009 Q7 hard brake pedal

Hey guys audi q7 2009 4.2 fsi no warning lights
No leaks , brake pedal goes hard and it wonr stop. Any suggestions on rhe best way to diagnose this.
I heard the booster are know to get water in it.
I have a few questions the eletric vacuum pump ,is suppose to run all the time . If i give it 12v it runs and pumps ,or does it only run wen needed.
The vacuum line coming from it should i run a smoke machine to see if i have any leaks in the lines. The brake booster vacuum lines are known to leak?

Hope to get help