Kovatch Mobile Equipment Corp. (KME) is recalling certain 2015 Predator SS Tanker and Commercial Pumper built on Freightliner chassis, 2015-2018 Predator SS Pumper and Commercial Pumper built on Navistar chassis, 2016 Predator Panther Aerial and Predator Aerial, 2015-2017 Predator Panther Pumper and 2018 Predator SS Aerial vehicles equipped with Hale pressure relief valves in the water pumps used for fire fighting. Rings securing the valves may corrode over time after exposure to water, causing the ring to fail and the pressure relief valve to open, reducing the water pressure available for fire fighting.