A method for forming a fuel cell assembly including the pre-final-assembly step of forming a plurality of fuel cell sub-assembly modules, each module including a predetermined number of individual fuel cell repeating units, for example, ten. Each module may be leak and performance tested and certified prior to inclusion in the final fuel cell stack, thus limiting potential rework to only an individual module and only before assembly of the final stack. Preferably, each module is assembled on an assembly fixture having alignment rods, using a combination of resilient gasketing and RTV to seal between the elements. The assembled module is then placed under compression while the silicone is cured.