Brake pump engaging making loud noise- is this normal? 2006 9-3
 

Hey guys, lately i've noticed that around 5-mph you will hear a noise coming out of the car, kind of like a thump...to be quite frank, if you keep your feet on the brake pedal you can feel something engaging. It is generally relatively loud...is this normal? Have any other 93 owners felt this? I took it to Saab today and the guy said it was a brake pump or something engaging...and its normal. I don't know if I believe that.