Abstract: A re-usable frame support rack is provided for supporting and retaining an outstretched, replaceable pleated-media filter core. The pleated-media filter core is of a type that has fold lines extending in a transverse direction and that stretches-out/collapses in the longitudinal direction. The support rack has a frame formed of spaced longitudinal rails extending between spaced transverse rails. The frame carries a pressure-differential support system that provides support, in instances when a pressure differential exists across the frame, to the filter core on a low pressure side thereof. The transverse rails preferably include fingers or like gripping formations for releasably gripping the longitudinal margins of the installed filter core. The longitudinal rails include gates or flaps which have closed and open positions for allowing retention and unobstructed removal in the closed and open positions, respectively, of the longitudinal margins of the installed filter core.