How is this Pella roller attached?

1) Remove the vent panel by lifting up on the panel while pulling outward slightly on the bottom. If the sliding door is equipped with a retaining angle, the rubber bumpers and handles must be removed so that the panel can be placed in the full open position. In this position the retainer angle may be removed. See picture below showing the retaining angle.

2) On models prior to Pella 701, remove the plastic protectors in the adjusting holes and remove the adjusting screw before attempting to pull out the roller asembly.
The roller assembly may be easily pulled out with the aid of a wire loop and claw hammer as shown in the picture below.
If the glass door does not slide smoothly after replacing the rollers, you may need to adjust the rollers to raise the door clear of the track. Adjust the rollers up or down to make sure the edge of the movable door is parallel to the side of the door frame. Use a long-shaft Phillips screwdriver to adjust the rollers. Turn the adjustment screw clockwise to raise the end of the door, and turn counterclockwise to lower it.