Jeep Repair: Steering humming/vibration, jeep cherokee, serpentine belt

Question
Hi, I have a 1998 jeep cherokee... and for a while now, I have been experencing a very fast vibration like feeling with a hum in my steering wheel. Not all the time, just when I make U-turns or any sharp/quick turn. It is quite annoying! I have taken it to my mechanic and he found nothing wrong. He said that maybe air is being sucked in the pump. Is this normal? Anything I can do about it? Thanks for your help!

Answer
My guess is that wear in the steering sector is starting to manifest itself in the vibration you are feeling.  I would not worry about it and monitor the situation if it gets worse.  You might want to have your serpentine belt changed.  It might make a different and in any event, if the belt is original, it's about ready to go anyway.