Abstract: A retractable sliding door apparatus includes a door housing, a sliding door slidably mounted in the door housing, and a retractable spring mechanism mounted to the door housing and to the sliding door for retracting an open door to a closed position. The retractable spring mechanism includes a spring drum having a constant force retractable spring attached to it and in which the constant force retractable spring has one end attached to a bracket mounted on the door. The constant force retractable spring is made of a spiral strip of steel which has been heat treated while coiled to a predetermined curvature so that when the steel is extended, the stress in the steel resists the loading force at an approximate constant rate so that the sliding door is opened against a generally constant force and returns from an open to a closed position at a generally constant rate of movement under the force of a constant force spring to thereby avoid the door slamming shut.