black water tank valve

Tank valve not closing all the way. Several gallons waste spilled out when cap removed. Any idea what is causing this?

Hey Jasbo, welcome to the forum. Lots of good information here.
Do you know which tank is leaking? I assume you have more than one. You did not say what model floor plan you have.
It sounds like you may have something stuck in the valve preventing it from closing all the way.
If it is the black tank, only drain it when there is a lot of water in it. Use plenty of water when flushing. And always use the rinser.
You might have to let it all drain out and then take the valve apart. I had to do that on a black tank valve a long time ago.
My wife no longer uses a half roll of TP at a time.
Let us know what you find.

Peace
Dave

In the meantime, install a spin on valve at the connection point for your sewer hose. You can then close the valve and keep from getting the dreaded shower when you remove the cap. Mine has been in place for 2 years. I've had no problems with it falling off on the road. I currently have a cable that's slipped leaving one of my gray tank valves partially open. I just haven't gotten enough ambition to drop the underbelly and fix it. It's been that way for over a year..I think they should be standard equipment on every trailer. I never plan to be without one...Don

You can also try one of THESE (Flush King) which may wash any obstruction out of the way.

Get the spin on valve. Also known as the uh oh valve. I made a saddle by splitting a 3/4" PVC T fitting down the center and screwing in a nipple to the T that when placed over the dump valve handle, the nipple against the outside wall in the UDC works very well to keep the black water valve closed.

Gaffer said:

Get the spin on valve. Also known as the uh oh valve. I made a saddle by splitting a 3/4" PVC T fitting down the center and screwing in a nipple to the T that when placed over the dump valve handle, the nipple against the outside wall in the UDC works very well to keep the black water valve closed.

Click to expand...

A picture would be worth a thousand words.

I agree with Steve. A Flush King might just be the ticket. You would be putting water in from the sewer hose side of the valve with a fair amount of pressure. It might be just the thing to dislodge anything stuck in the valve..Don