Wheel Bearing/CVJ problem??

[Anthony Attard <ACA@nrc.gov>]

I would like to thank all of you who responded to my master
cylinder problem.  I have a question about wheel
bearings/CVJs on my 89 Audi Model 90 Q.
  

About a week ago I replaced the drivers side wheel bearing
because it was making a hell of a noise. So jacking the car
on 4 stands, I ran the car and put a stethoscope on all 4
hubs, until I found which bearing was responsible for the
noise.  I had no problem replacing the bearing.  In the last
couple of days, I began to hear the same noise again, and I
think it is coming from the same wheel.  I have not had the
chance to jack the car back up to see if indeed the noise is
coming from the wheel or from another corner of the car.  I
intend to that tonight.  Anyway my question is this:

 1.  Is it possible that the new bearing went bad already?? 
 
 2.  How does one tell whether its a noisy wheel bearing -  
     VS - noisy CVJoint ?? 

 I appreciate any input since I hope to attack this problem 
this afternoon/evening.   Thanks much everyone.



Tony .   89 Audi model 90/Q