A surge suppressing check valve, in its closed condition, closes a fluid passage and separates it into inlet and outlet portions. A cylinder communicates with the outlet portion. A first piston closes the cylinder adjacent to the outlet portion and is axially movable against the urging of a compression spring to enlarge the volume of the outlet portion of the fluid passage for suppressing pressure surges therein. A second piston is provided for pre-loading the bias spring, the pre-loading being selectively variable via a threaded stem and nut connected to the second piston. The first and second pistons are coupled together so that the entire assembly can be removed from the housing. Means are provided for removing fluid from the housing.