Metering diaphragm pump having a front removable hydraulic refill valve

A hydraulic refill valving apparatus can be removed from the front of a metering pump without requiring the entire displacement chamber to be removed from the pump drive mechanism. The valving apparatus separately mounts a mechanically actuated refill valve and a refill check valve such that they can be removed from the front of the pump with relative ease, leaving the displacement chamber connected to the drive mechanism with the sealing gasket therebetween. By separating the refill valve and refill check valve functions into two separate assemblies, the apparatus is made more reliable in that it is less susceptible to problems encountered with relatively high viscosity working fluid.