there is a screw into one side of shoe holding it into place, how do I access this screw in order to remove the shoe to replace it with the new 15-177 shoe
First tilt and remove your window sash. Then with a large slot screw driver, slide it the screw driver into the locking cam and turn it to release and slide the pivot shoe up to meet the spring coil. Unscrew the spring and remove the spring and shoe. There should be a cut out in the track to remove the shoe (if there is no cutout see this discussion about removing the pivot lock shoe). After you remove the pivot lock shoe, you can get to the side screw.