Joe, thanks for suggesting Sew-Classic.
Treadlep, you are right, that spring is inside the metal tube on my 99. I had adjusted the knob screw but saw no results. After reading your post I removed that screw and poked on the rod and it barely moved. So I pulled the rod out and poked inside the tube with a dental pick. The spring felt like it was jammed, or caught, inside the tube, so I gently pushed and pulled at it until I felt movement. I replaced the rod and screw and now there is more pressure on the foot. I just wasn't happy with how much "play" the fabric had under the pressure foot and didn't think it was because the machine is being handcranked. Thank you for your help!