A double diaphragm pump includes multiple diaphragms that are mounted for reciprocation. The diaphragms are connected for simultaneous movement to form a diaphragm assembly. A first one of the diaphragms is clamped between a housing cover and a center section. A pumping chamber is formed between the first diaphragm and the cover. Pressure in the first pumping chamber is decreased to draw the diaphragm assembly towards the first fluid cover, thereby drawing the second diaphragm into a mounting position relative to the center section. A second cover is then mounted to the center section to clamp the second diaphragm between the second cover and the center section.