replacing pump fitting

[spriteman]

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?

thanks

 

[jblizzle]

1. Yes the fitting screws in. You should not need any silicone, but use a good teflon pipe dope.
2. Ideally you want most out ... if it is a silicone rubbery sealant, that may be more work to try to remove.

 

[spriteman]

thanks jason ..... was able to pick up some Rectorseal Tru-Blu at home depot. it's teflon based and says it is specifically formulated for vibration areas -- I figured the outlet to the pump qualifies as a vibration area. not sure how long it takes to cure since the directions state it "varies with application". so, i went ahead and removed the old fitting and installed a new one using the tru-blu and replumbed the 2" line. the old sealant wasn't too hard to remove -- it was basically limited to the first few threads.

 

[jblizzle]

Make sure that pipe dope says it is for PVC and ABS, some can damage plastic.

 

[spriteman]

right .... I checked the label beforehand -- says it's good to use on pvc, cpvc, PE and FRP plastic pipe

 

[jblizzle]

What are the pumps made of? I have read some multi valves are ABS and get weekened and crack from the wrong dope.

 

[spriteman]

not sure what the pump housing halves are made of, but they kind of look like a fiber reinforced plastic or some kind of resin material ....