The presser foot release lever on singer machine is not working?

Is there an easy way to fix my pressure release foot on Singer sewing machine 9018. I started to change a foot and I thought the foot Shaft was loose but in trying to tighten it I seem to have upset something. At one point the pressure lever wouldn't go up it seemed to be blocked, and now it will raise but it is not holding the shaft up. I am sure it is something simple that I am not seeing. Hope this makes sense.
thanks

Gill Best
April 2008