A warewash machine arm mechanism includes a liquid supply shaft assembly including a rotatable sleeve bearing mounted thereon, and an arm assembly including an elongated interior liquid flow space along an arm body and one or more liquid ejection orifices. The arm assembly is releasably mounted to the supply shaft assembly via a latch mechanism of the arm assembly that engages the rotatable sleeve bearing such that the arm assembly rotates with the rotatable sleeve bearing during ejection of liquid from the liquid ejection orifices.