A system and method for assembling a door to a motor vehicle is disclosed including a bracket assembly that includes a bracket having a first pair of holes and a second pair of holes, and weld nuts welded to the bracket, the weld nuts being aligned with the first pair of holes. The system further includes an alignment piece having first and second alignment holes, the first alignment hole corresponding to a first of the second pair of holes of the bracket, the second alignment hole corresponding to a second of the second pair of holes of the bracket, datum pins inserted through the first and second alignment holes and the second pair of holes in the bracket, and a roller assembly fixedly attached to the bracket.