CompuServe Messages

I have a ball that can move in the Z and X axis. I want an object that is linked to the ball to only move in the Z axis. I used Link Info and read the instruction and The linked object moves in all direction as the ball. What am I doing wrong. The object is Linked first and I click on Link Info, I click off all buttons for scale and click off buttons for X and Y. What am I missing Raymond Stivala