Someone emailed me about their leaking fuel sediment bowl and so here is the info on the usual culprit. The valve stem is 99% of the time defective as the rubber seal in it gets chewed up and torn then fails. The valve stem can be purchased separately, and is a lot cheaper, $5/$6, than buying a whole new sediment bowl assembly. The valve stem is the only working part. The body has no working parts but if the inlet threads get boogered up, won't seal fuel lines. I always use dab of Loctite Thread Sealant on the little #8-32 screw that secures the knurled valve stem knob/handles onto with so it doesn't unscrew and fall off in the field working.
N-Series Fuel Sediment Bowl Valve Stem Replacement: