2021 Adventurer 29b Leaky Black Water Tank

[johntk]

My tank open/close valve is operated via a cable. It appears to not close all the way and I have a minor leak which causes quite a mess when dumping. None of my local RV repair shops are interested in working on black water tank problems.
I'm asking for any suggestions on how to fix this problem.

Thanks,
John

 

[youracman]

I found several videos on youtube helpful when I replaced my gray water valve seals. It's a 1-1/2 inch valve where the black is 3" ....... but they are the same design. If your valves are Valterra the videos should help. In my case, the PO of the coach took his kids to the CA beaches a lot (good idea) but some grains of sand found their way into the valve (from the inside shower, probably) and a leak resulted. Sounds like new seals for your black valve are in order. Time to flush the tank as thoroughly as possible and go to work. Here's a couple of videos: one is a basic primer (note the caution comment re tightening the 4 bolts too tight.) The other vid shows a guy replacing the seals in a 1-1/2 inch valve. (Hope your black valve is more accessible.) BTW- Mine is cable operated too; doesn't affect the seal replacement job. Another thread here on the forum recommends using silicone grease on the new seals. I didn't do that, but I would next time. Good luck with the fix.

 

[Rene T]

I had the same issue with my cable operated valves. You get a little crap in the track for the valve and when trying to close the valve the cable sort of doesn’t allow the valve to close.
I did two things to fix my issue. The way by tanks are situated, I was able to remove the cable assemblies and go directly to the valve through my frame with a solid metal rod extension.
The other thing to do is install a Camco spin/twist on valve on the end of your sewer pipe. My valve stays there all the time. This way if any of my valves are leaking, the fluid stops at this valve. No more surprises.
Another benefit is after dumping your black tank you can shut this valve then open your gray tank valve. This valve being shut allows you to transfer water from the gray tanks to your black tank to allow you to dump the black tank again. I can do this a couple of times.

 

[johntk]

Thanks for the replies and suggestions. My tank/valve are not handy to get to. I have installed a twist on valve at the end of the sewer pipe. Due to lack of space I'm having to add a 90 degree connection and cut-out part of the bottom of the bay in order to attach a drain hose. Just got the connection today so haven't installed it yet, but should work.

Thanks again,
John

 

[johntk]

Thanks for the replies and suggestions. My tank/valve are not handy to get to. I have installed a twist on valve at the end of the sewer pipe. Due to lack of space I'm having to add a 90 degree connection and cut-out part of the bottom of the bay in order to attach a drain hose. Just got the connection today so haven't installed it yet, but should work.

Thanks again,
John

 

[johntk]

Thanks for the replies and suggestions. My tank/valve are not handy to get to. I have installed a twist on valve at the end of the sewer pipe. Due to lack of space I'm having to add a 90 degree connection and cut-out part of the bottom of the bay in order to attach a drain hose. Just got the connection today so haven't installed it yet, but should work.

Thanks again,
John

Update: I used a saws-all to widen the sewer hose opening enuff to install a 90 degree hose adapter onto the twist-on valve extension.
When traveling I lay a single floor mat over the opening. When camping I close the tank valves and leave the extended valve open so there's no build-up of liquid.
It ain't particularly pretty but it's all working well.

 

[Rene T]

Thanks for getting back to us. Have any pictures?

 

[johntk]

Thanks for getting back to us. Have any pictures?

Lots of hoses in the way but I think you can get the idea. The floor mat on the left is what I use to cover the hole when traveling.
View attachment 161130

 

[Rene T]

Good job. Thanks for the pictures

 

[rider1520]

I have the same model and have found that there must be a flat spot in the plumbing. after I empty the black tank there always seems to be about one cup of waste that lays in the pipes somewhere. Traveling seems to move it to the end so when I go to remove the cap I always have a small container available to catch that amount. It's always about one cup. I have also removed the cap once I got to my next destination BEFORE I dumped and then when I go to dump everything is fine. so it must be a flat spot in the plumbing

 

[Rene T]

I have the same model and have found that there must be a flat spot in the plumbing. after I empty the black tank there always seems to be about one cup of waste that lays in the pipes somewhere. Traveling seems to move it to the end so when I go to remove the cap I always have a small container available to catch that amount. It's always about one cup. I have also removed the cap once I got to my next destination BEFORE I dumped and then when I go to dump everything is fine. so it must be a flat spot in the plumbing

That’s easy to fix. Install a spin on gate valve by Valterra or Camco and mount the cap on that valve. Then when you remove the cap, it will be dry. Then after hooking up your sewer hose, open that valve. No more surprises.
This valve is great if you have a tank drain valve leaking by a little like you obviously have.
Also, on my rv, all my tanks share the same outlet where my spin on valve is. When it’s time to dump, I make sure my gray tanks are full. Then after dumping the black tank, I shut that spin on valve and open my gray tank drains. That water transfers to the black tank till the level equalizes. Then I shut the gray tank valve and open the black tank again. You’ll be surprised how much solids come out from the black tank. I also use a 45 degree clear elbow on that valve so I can see the output. I’m able to do this process at least three times. Then what’s left in the gray tank, I use that to flush out the hose.

OOPS: I just realized that I wrote the same thing in post #3.

 

[johntk]

I have the same model and have found that there must be a flat spot in the plumbing. after I empty the black tank there always seems to be about one cup of waste that lays in the pipes somewhere. Traveling seems to move it to the end so when I go to remove the cap I always have a small container available to catch that amount. It's always about one cup. I have also removed the cap once I got to my next destination BEFORE I dumped and then when I go to dump everything is fine. so it must be a flat spot in the plumbing

Mine is much bigger than a flat spot. It is a definite leak. I got surprised a couple times before I installed the extra valve and extension.