Black tank valve cutaway views a PSA

[Upinsmoke]

I've seen a post or two where someone has a black tank somewhat/full of what black tanks hold, and the dump valve is stuck closed. Obviously, not a good situation. Recently my black tank valve had become more difficult to operate and, not wanting to be in the above mentioned scenario, I preemptively changed it.

I had also seen/heard where people had drilled holes in them around the handle/rod and either put in a grease fitting or a screw for spray lube. I decided that since I had a used one handy, it might be nice to cut it open (see pics) and see how they are put together and whether either of the above would work as a temporary fix.

First let me say that when you see how "dirty" our valve was on the inside around the slide, it's easy to see why they get difficult to operate. It also shows why I wouldn't put grease in there as a lube.

My conclusion on all of this is that if you find yourself with a stuck valve, if you can move the handle even a little, spraying the area where the shaft enters the housing (green arrow) with a "good" spray lube might allow you to open the valve further, or all the way. Failing that, I would drill a hole in the housing (red arrow) and use the spray there. However, if I had to go to these lengths, once the tank was empty, I'd have a new valve on hand to replace the old one.