The invention relates to a window lift system of a vehicle door with a first component, wherein the first component is designed for the fixation at a window, wherein the first component can be inserted with the window into a first position in the vehicle door, and with a second component, wherein the second component can be attached to the vehicle door in a detachable manner, wherein the second component is movable from the second position to the first position, and wherein the first component can be connected with the second component in the first position. In other aspects, the invention relates to a method for mounting of the lifter, a first component, and a second component. The invention further relates to a tool for mounting of the lifter.