I have a dura-glas P2R series pump that developed a crack in the fitting that attaches to the pump body discharge. the fitting is a 2" on the pipe side and 1.5" on the pump side (this is stamped on the fitting itself). I'm assuming the fitting threads into the pump body. the reason I say this is it appears there is a silicone based sealant (blue in color) that I can detect at that interface. when I first saw the sealant, it reminded me of RTV since I could press my fingernail into it and it had the feel of something rubberized/pliable.
just to be clear, the fitting is cracked NOT the pump body.
my main questions are: 1) are all my assumptions valid and what kind of silicone do I use when I replace the fitting? 2) also, do I have to remove every last morsel of old sealant from the pump body threads at the discharge? -- I guess what I'm asking is how clean do I need to make it before loading it up with new sealant and installing a new fitting?