On my 1998 Buick Park Ave the tilt-wheel will no longer change positions. A couple of days ago I got in the car, adjusted the steering wheel and heard something Pop.
Since then, the steering wheel will only stay in that position.
Does anyone know how I might go about fixing this problem?

Thanks in Advance.

You will probably have to buy the Haynes or Chilton manual for the car.
It will involve removing the steering wheel to gain access deeper into the
Column to find the source of the problem. If you decide to take on the job
It is Important {if there is an airbag on the wheel} to read how to disarm
The bag prior to removing the steering wheel and how to re-arm the bag
After the job is complete.