Looks like I need to Replace the Black tank knife valve

gspdx
gspdx Member Posts: 208
in Heating/Plumbing & Winterizing
It seems the flange that the black tank knife valve is attached to has a crack.  So I believe that flange is glued to the 90 degree elbow and that elbow is attached to the tank.  Has anyone replaced all of that?  Just wondering how much of a problem is will be connecting the elbow back up to the tank.

Thanks.


2019 T@B 400 BDL
2018 Ford F-150 2.7L Ecoboost with tow package
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  • gspdx
    gspdx Member Posts: 208
    This is a 2019 T@B 400
    2019 T@B 400 BDL
    2018 Ford F-150 2.7L Ecoboost with tow package
    PNW
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  • Dalehelman
    Dalehelman Member Posts: 2,414
    edited June 2019
    That flange is glued to the 90* elbow and is impossible to separate. It can be cut off and the elbow rebored with a special 3” cutting tool. First I would buy a can of ABS cement. Clean the surface with sand paper and steel wool. Then apply a liberal coat of the cement. That will usually take care of most cracks.

    This is is the tool needed to save the elbow.

    PlumBest J44300 J44-300 3" PVC Socket Saver, 3-Inch 
    PlumBest
    $15.50
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  • gspdx
    gspdx Member Posts: 208
    Nice.  Didn't realize they made something like that.  I was thinking about replacing all the way to the tank.  

    I have abs cement.  Will try that first.  Maybe remove the knife valve and coat on the inside too?
    2019 T@B 400 BDL
    2018 Ford F-150 2.7L Ecoboost with tow package
    PNW
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  • Dalehelman
    Dalehelman Member Posts: 2,414
    Igspdx said:
    Nice.  Didn't realize they made something like that.  I was thinking about replacing all the way to the tank.  

    I have abs cement.  Will try that first.  Maybe remove the knife valve and coat on the inside too?
    If it is threaded into the tank know problem if it is glued in not so good. Let us know what you find. My guess is that it is threaded.
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  • ChanW
    ChanW Member Posts: 3,165
    Is it not under warranty?
    Chan  -  near Buffalo NY
    2014 S Maxx
    2011 Tacoma 4cyl ... edit: 2022 Tacoma 6cyl - oh yeah! 

     A_Little_T@b'll_Do_Ya
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  • gspdx
    gspdx Member Posts: 208
    I actually bought this used.
    2019 T@B 400 BDL
    2018 Ford F-150 2.7L Ecoboost with tow package
    PNW
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  • gspdx
    gspdx Member Posts: 208
    Dalehelman said:
    Igspdx said:
    Nice.  Didn't realize they made something like that.  I was thinking about replacing all the way to the tank.  

    I have abs cement.  Will try that first.  Maybe remove the knife valve and coat on the inside too?
    If it is threaded into the tank know problem if it is glued in not so good. Let us know what you find. My guess is that it is threaded.
    I called Nucamp today and they had me email the repair guy with some photos.  Will let you know what he says.  Might take a few days as they are having their annual gathering this week.
    2019 T@B 400 BDL
    2018 Ford F-150 2.7L Ecoboost with tow package
    PNW
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  • gspdx
    gspdx Member Posts: 208
    OK - I still haven't gotten a reply from Nucamp on this.  I called again and they suggested I email again which I did.  So I have called twice and emailed twice.  The did say they are very busy with maintenance and I get that, but it is a little frustrating.  

    Anyway - I decided to try the suggestion from Dalehelman.  I cut off the flange on the 3" spigot that the valve mounts to.  I then used the 3" PVC socket saver.  Had to come in at a little bit of an angle since the gray water drain is in the way a bit.  So when I finished using the boring tool there was a little bit of the spigot pipe still in the elbow. I chiseled that out, sanded it and glued it up with a new spigot.  Waited to the next day to reassemble and water tested last night.  Everything looks good.  For me the easiest way to reassemble was to do the 3 inch valve first. Put the gaskets on the pipe ends and assemble the valve. tighten each bolt a little at a time so the whole assembly compresses on the gasket evenly.  Get it tightened and complete.  Then put the gaskets on the pipe ends for the 1.5 inch valve.  Pull the pipes apart just enough to slide the valve in without moving the gaskets.  You might need a third hand at this point.  You just need to make sure those gaskets don't move.  Once it is in place hold it while you insert the screws and hand tighten.  Finish in the same manner as the first.

    I was thinking about replacing the entire 90 degree elbow.  When I got in there to see how that was connected it goes up through the floor - pretty tight hole - and I could see a band clamp with sealant around it.  I tried to get a socket on it and there just wasn't much room.  If I need to get up and replace that I think I would need to cut a little bit of the floor away.  If I do end up with any leaks I can still do that.  

    So I still don't know if there is a threaded fitting up in there or not.


    2019 T@B 400 BDL
    2018 Ford F-150 2.7L Ecoboost with tow package
    PNW
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