Set ahead and set back: As shipped, the scraper is set in its center position. For tractors with larger tires a user may wish to set the blades back. To do this remove the 2 silver pins mentioned in Tip 2. Remove the center pivot assembly nuts and bolts. Align the center frame bolt holes with the pre-drilled bolt holes on the front of the scraper. Refasten the center pivot assembly nuts and bolts and re-insert the silver pins. For set ahead follow the same procedure except use the pre-drilled rear bolt holes.