Black tank valve not completely sealing

The push/pull dump valve on my black tank is not completely sealing after dumping.  I am getting a very, very slight trickle from it.  I?m guessing there might be debris caught where valve closes.  I have tried flushing several times and also using wand from the inside.  Are there any YouTube videos showing how to replace this?  Only ones I find are for the outside valve that you connect dump hose to.  I have a sealed underbelly and have not removed it yet.  Thought I would get advice from the pros here.  As always all suggestions appreciated.

clockdrfla said:

The push/pull dump valve on my black tank is not completely sealing after dumping.  I am getting a very, very slight trickle from it.  I?m guessing there might be debris caught where valve closes.  I have tried flushing several times and also using wand from the inside.  Are there any YouTube videos showing how to replace this?  Only ones I find are for the outside valve that you connect dump hose to.  I have a sealed underbelly and have not removed it yet.  Thought I would get advice from the pros here.  As always all suggestions appreciated.

Click to expand...

Worst case scenario, you are going to have to get to the valve by either dropping the belly or by locating the exact spot of the valve and cut a access hole to get to it. Some of us keep a valve mounted on he end of the sewer pipe just to prevent any surprises when removing the sewer pipe end cap. You could install one of those spin on valves, shut it, open the leaking valve then fill the tank all the way up so that the valve is completely under water. You then could add some septic chemical like Ridex or Roebic K57 and let it set for several weeks if you can. This may dissolve whatever is causing the leak. 

https://www.amazon.com/Roebic-Laboratories-Septic-Treatment-32-Ounce/dp/B000BQU7IS/ref=sr_1_2?s=home-garden&ie=UTF8&qid=1539040427&sr=1-2&keywords=roebic+k57&dpID=51S08dkgziL&preST=_SY300_QL70_&dpSrc=srch

clockdrfla said:

The push/pull dump valve on my black tank is not completely sealing after dumping.  I am getting a very, very slight trickle from it.  I?m guessing there might be debris caught where valve closes.  I have tried flushing several times and also using wand from the inside.  Are there any YouTube videos showing how to replace this?  Only ones I find are for the outside valve that you connect dump hose to.  I have a sealed underbelly and have not removed it yet.  Thought I would get advice from the pros here.  As always all suggestions appreciated.

Click to expand...

I had that exact same problem with the fiver I bought last year. I tried everything to fix it and gave up. Since I am parked permanently I bypassed the holding tank and plumbed the toilet straight to the sewer (well I didn't do it, Catblaster graciously did it for me, thanks Will).

I have a similar problem with my gray tank, but it is more than a trickle.  I have a valve on the end of the drain pipe, plus a cap.  When I dump, I pull the cap (no drips), connect the hose, then open the drain pipe valve.  I continue a normal dump procedure.  When all is empty and flushed, I close the drain pipe valve, disconnect the hose and cap the valve.  So what if it leaks INTERNALLY?!

Update.  Did what Rene T suggested.  Closed Valterra valve, opened black tank valve and kept flushing at five minute intervals.  During flush I would open and close black tank valve by using the push/pull tee handle.  It worked.  Valve completely sealing and no seepage at all.  Thanks to everyone for the suggestions.

clockdrfla said:

Update.  Did what Rene T suggested.  Closed Valterra valve, opened black tank valve and kept flushing at five minute intervals.  During flush I would open and close black tank valve by using the push/pull tee handle.  It worked.  Valve completely sealing and no seepage at all.  Thanks to everyone for the suggestions.

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Glad it worked out for you and thanks for getting back to us with the results.
I would still recommend installing a spin on valve on the end of your sewer pipe just in case it should start leaking again.

https://www.amazon.com/Valterra-T58-Twist-On-Waste-Valve/dp/B000BGHYJS