Generally fuel pumps only need to be replaced because they get a hole in the rubber diaphram and begin to leak. They have a hole in them for this fuel to come out of, like a water pump.

Take care,
Rick
68 Coronet R/T 440 & 68 Charger 528 Hemi,and 5 Challengers! 6 cyl, 318, 360, 383, 451