Black Tank Valve

[K&Gs3400RL]

My pull handle no longer opens the valve for the black tank. Help I can't take it off to replace the tank is full? Is there a way to disconnect it and open it from below?

[waynemoore]

You may be able to reach the unbroken part of the pull with a long pair of needle nose pliers.

[BuilderBob]

I had that happen on my SOB one time and I was able to cut the cover off to get at the cable to open the dump valve maybe you can do the same. I did right a the valve.

[Montana Man]

Like that^^^

I suggest replacing both those cheap cable pull valves with direct pull valves. I did it. Just get the extension rod and run the rod through a hole in the frame. It is that simple. Those cables are disasters waiting to happen as you now know.

[1retired06]

To answer your question, you have to access thru the underbelly, drop or cut an opening, and you can manually open and dump. Agree with Montana Man, I have also replaced failing cable pulls with direct pulls. Mine was not as simple to install as described above, but not all that hard either. Did require some plumbing rerouting and cable pull relocation.

[K&Gs3400RL]

Update.....
I have the pull cable disconnected, and can pull the valve open with my hand. But still nothing comes out. Not even water if I turn on the flush valve. But the tank sounds empty when water is going in. If the vent to the roof is blocked will that stop the sheet from coming out? I would think water would at least trickel out.

[Bierp]

Don't think the roof vent can fully prevent it from flushing. If you're opening the valve in the toilet, that would break any kind of vacuum seal. Even if it was sealed, the weight of a mostly full tank would rush down the hose and if it required pressure regulation I'd expect it to pull back up from the hose, similar to how a bottle empties when you hold it fully upside down.

Of course, I'm no physicist.

[Montana Man]

If you hit the bottom of the tank you should be able to tell if it has anything in it or empty. If the valve is indeed pulled open, something will come out even if clogged. Venting problems at this point is unlikely. What does the electronic tank level indicate? If the tank empties to the rear of the trailer, raise the front high. Something has to come out. Do you have a clear elbow at the sewer hose connection so you can see all of what comes out of the tank? It sounds like a massive clog or valve not opening.

[richfaa]

As our holding tanks failed we had quantity dump cable assemblies installed one all of them.

[maximo]

I changed over to electrical push button valves on all three tanks. If switch does not work you can still open the valve by hand. Had it done at a RV shop. Cost was around $900. Will have to see how that works out. So far it is great.