A self-aligning tractor axle mounted tank system for vertically mounting a tank to a tractor is provided comprising an integrated hub and spindle, a housing connected to the spindle so that the spindle can rotate with respect to the housing, and at least one housing bracket connected to the housing and adapted to mount a tank frame assembly, wherein the housing bracket is configured to align the tank frame assembly with the housing during vertical mounting. Additionally, an integrated hub and spindle assembly is provided comprising a spindle connected to a hub, and a bearing housing connected to the spindle so that the spindle can rotate with respect to the bearing housing. Furthermore, a process for mounting a self-aligning tank to the rear axle of a tractor is provided.
