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Waste Water Valve Replacement


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#1 Hot Toddy

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Posted 13 February 2018 - 03:06 AM

I think I need to replace the 3" waste water valve on my trailer as I have noticed more and more seepage collecting when I remove the cap for dumping my tanks. Question, do you recommend simply replacing the affected valve, or is it easier to replace the entire assembly as pictured below? I am not a huge fan of fixing/replacing something before it is broken, but while I am at it should I replace the 1 1/2" valve too? My trailer is 5 years old, so I assume these valves get tired after time. Thanks!





Valterra Bladex Waste Valve.jpg


Valterra T80 Double Waste Water Valve .jpg


#2 thetravelkids

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Posted 13 February 2018 - 03:32 AM

You only need to replace the valve. And yes, I’d replace the gray valve while you are at it. Cheap insurance.
Not as difficult as you may think....just ensure you’ve emptied both tanks as much as you can. Most likely you still have some “stuff” in the pipes.
Put a drip pan underneath. A roasting pan from the dollar store works great and then dispose.
Good luck.

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#3 Meadowlark

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Posted 13 February 2018 - 09:02 AM

Toddy, I replaced the gray water valve O-ring myself. It was NOT an easy job and I wish I'd just gone the route of replacing the entire assembly. The problem is that the 'gap' between the two mating flanges is so very tight that you can't slip the O-ring in and get it seated all way round without it buckling, pinching,  or getting hung up. In the end it was a botched job, and so we just bought Larry's Fast Drain Gray and will install that.


and, as the travelkids advise, DO make sure everything is drained, clean and dry before you try it. Nothing nastier than effluent....

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#4 Mark P

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Posted 13 February 2018 - 01:14 PM

Regarding the "complete assembly" pictured in your lower photo.  It may seem like going the "complete assembly" route makes sense, but it really doesn't. Keep in mind that you will be discarding both female pipe flanges (unless one of the existing flanges is broken and needs replacement, in which case you will be needing to replace a section of connecting drain pipe too).  Thus, after having discarded the flanges all you have left are the two valves and the center Y section.  Unless your existing center Y section is broken, you don't need to replace it.  So now, all you have left are the two valves.


Replacing a whole valve, like you pictured in your upper photo is not expensive.  But you probably only need to replace the Bladex valve seals which is even less expensive.  In either case, the process to replace a whole valve or replace just the seals is the same.  And, as Meadowlark mentioned above, it can be a challenge to insert the valve with seals because of tight space between the two mating flanges.  The trick I found is to disconnect the pipe hangers on black and grey pipes.  This will give you enough "flex" to open the gap between the two mating flanges enough to insert the valve and seals.


And, yes, as long as you are doing one valve, do both.  Just remember do only one valve at a time before removing the other valve (it will be easier).


It is not hard to do:  


Edited by Mark P, 13 February 2018 - 01:19 PM.

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#5 Hot Toddy

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Posted 16 February 2018 - 11:17 AM

Thanks for all of the advice folks! I believe I will proceed accordingly:

1) Flush the drain well and hopefully dislodge any "grit" that may be preventing a good seal. I have been meticulous about my black/grey tank maintenance and use a good quality treatment chemical, so I am hoping for good results.

2) Replace the seal on both the black and grey valves.

3) Replace the valves on both the black and grey valves.


Obviously I will stop at the point where one of these solutions works. Ha!



#6 Mark Watson

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Posted 16 February 2018 - 01:34 PM

I opened up the pipe support clamp on the grey side and this gave me about 1 inch of a gap in which to maneuver the old valves and seals out, and install the news parts into position easily.Failing to do this will turn an easy job into a difficult one as mentioned above.

Mark Watson

2008 17' FD

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