An unpowered, self-elevating and self-lowering home appliance assembly cart for supporting and transporting a plurality of home appliance assembly components, such as oven doors, including a base, and a self-leveling and self-lowering door suspension and supporting system having a mast, a rail system moveably coupled to the mast, a plurality of arms extending from the rail system, each pair of arms for supporting a home appliance assembly component, and a self-leveling and self-lowering device that automatically self-levels and self-lowers the pair of arms within a predetermined acceptable ergonomic work zone with respect to a vertical height along the mast based on an unloaded state, a partially loaded state, and a loaded state of the plurality of arms and without power assistance, the predetermined acceptable ergonomic work zone being for loading and unloading the home appliance assembly component from the pair of arms.