A window assembly for a vehicle having a body structure with a window enclosure, and a method of installing a window, is disclosed. The window assembly includes a window and a window regulator bracket assembly. The window is slidable into the window enclosure. The window regulator bracket assembly includes a support rod having an upper end mounted to the body structure and a lower end with threads. The window regulator bracket assembly also includes a spring housing slidably received on the lower end of the support rod, a compression spring, a support nut threadably received on the threaded portion in engagement with the spring plate, and a support jaw engaging the bottom edge of the window. The support nut is screwed onto the support rod against the bias of the spring to secure the window in its closed position.