According to one aspect, a pump assembly includes a fluid cylinder, and the fluid cylinder includes a fluid passage that defines a tapered internal shoulder of the fluid cylinder. The tapered internal shoulder defines a first frusto-conical surface. A valve controls flow of fluid through the fluid passage. The valve includes a valve seat, which includes a seat body disposed in the fluid passage, and a bore formed through the seat body and through which fluid flows. The seat body includes inlet and outlet end portions, wherein the fluid flows into the bore at the inlet end portion and flows out of the bore at the outlet end portion. The inlet end portion of the seat body defines a second frusto-conical surface. In one embodiment, the second frusto-conical surface engages the first frusto-conical surface to distribute and transfer loading.