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groundhogy 06-26-2020 06:37 PM

Gate/Dump Valve suggestions..
Seems my black water tanks gate valve is closed and is not opening.

Im still trying to learn where this problem is going to take me...

... im not so sure I like what Im learning so far.

Can anyone give me any tips?

BayouBiker 06-26-2020 07:07 PM

The handle is stuck or the handle moves but nothin' happens?

groundhogy 06-26-2020 07:11 PM

The tee handle moves but the gate stays closed

groundhogy 06-26-2020 07:14 PM

So I’m imagining myself crawling under the full tank of poo, then I have to unscrew things in order to fix it...

BayouBiker 06-26-2020 07:15 PM

the handle is an extension from the short valve stem. It is often riveted or cotter pined together, You'l neet to gin access to the shorter stem and refasten it.

Edit: well yeah there's that.....

groundhogy 06-26-2020 07:18 PM

I like that answer.

How to gain access to where the tee shaft cotter pins to the gate?

groundhogy 06-26-2020 07:23 PM

Sounds like it is inside the thetford? valve?

Bill M. 06-26-2020 07:24 PM

The handle is connected to the gate valve by a long aluminum rod. The connection between the gate valve and the handle has failed. You need to get into the space in which the connection is made. On my trailer that meant grinding a cutout in the galvanized pan under the area. You might be able to push the rubber flap that the extension rod runs though out of the way enough to see the connection and to see how to put it back together. It probably is connected with a pop rivet or a cotter key. You might be able to fix it through that hole or by enlarging that hole. Or maybe reach in with a set of those long nosed pliers or clamps from harbor freight. It has been awhile since I worked on the dump valves and I do not remember exactly how far in the connection is. I think you may be able to reach it. Was the valve working well before the connection failed?

If your dump valves have ever been worked on there is already a big cutout with a sheet of aluminum screwed or riveted onto the large galvanized pan. That is how Airstream and most other places access the valves. You take that patch or cover off and you will be right in there to work. If it is riveted you will need to drill the rivets. Use a stop block on the drill and wear safety glasses.

tjdonahoe 06-26-2020 07:46 PM


Originally Posted by groundhogy (Post 2376101)
The tee handle moves but the gate stays closed

.....on our 13 31 Classic. The rod and extension was held together with a rivet....I dropped the cover down part way..held up with blocks..and used a cotter key...:D

groundhogy 06-26-2020 08:13 PM

There is a pan/cover there already. Its attached by screws. I had it partly open this morning and got a peak. What i saw was the rod entering the gate valve. I saw no external cotter or rivet if I remember correctly.
When i pushed/pulled the rod tee handle, i saw the rod at the thetford go in and out.

So the cotter/rivet is inside the valve?
I need to open it up further and take pics and document what i have.

CRH 06-26-2020 08:17 PM

The rivet is not inside the valve. It is easy to see.

How do you know the valve isnt opening? Is there anything in the tank that should be coming out?

groundhogy 06-26-2020 09:03 PM

The valve was working the other day, as i have been successfully dumping. But I noticed the black tank was filling up quite fast, so i called the tank cleaner guy over. He sticks a pressure wash hose up in the tank and washes it all down.

He couldn’t get his hose passed my black tank gate.
So i guess the cotter/rivet decided to break at just the moment he used it. Lol

So i know there is something in the tank. If you take a flashlight and look down the toilet hole, you can see the pyramid. But maybe its too dry?
I should run some water in the toilet and watch the outside exit to see the water come out.

SeeMore 06-26-2020 10:54 PM

You may find the responses and pictures in this thread of value:

groundhogy 06-26-2020 11:20 PM

SeeMore said this in the link to the other post...
“Once a gasket moves and gets disfigured, your solution is to rebuild the valve assembly with new gaskets.”

Rebuild? Tell me more. I have seen this rebuild word before in reference to the thetford valve.
If i remember correctly, it was in my own airstream manual. Saying my gate valve might be a glued on type or a non-glued on type.

groundhogy 06-26-2020 11:28 PM

So here’s a question:
If i see the rod, that is part of the thetford valve, going in and going out, is it even possible that the the gate inside the valve is not moving in and out also?
ie. can it detach inside the gate valve? Does that ever happen?

Bill M. 06-27-2020 08:43 AM

Maybe, with a lot of luck, you have a blockage in the tank at the head of the tank. Run a flexible rod into the sewer opening and see if you can feel the gate of the valve or see if it moves. But I suspect the problem is the valve.

If not, at this point, you need new valves whatever the problem in the valve is. I have rebuilt a set of Tetfort valves and have replaced a set. And I paid Airstream a fortune to rebuild the set I replaced before I had to replace them. I am really mad at Airstream for insisting that the rebuild was cheaper and sufficient. Neither was true. My suggestion is to replace both valves. You can get them from Outdoors mart or Amazon. I went with Outdoors mart because I knew I would get the correct valve. The only thing in the rebuild kit are gaskets. No replacement for the slide or the shaft. Go with the new valves. It might be educational to order a valve to just look at. It sounds like the valves have been rebuilt at least once already.

My trailers are 1988 models. The valve attaches to the tank with a slip fitting and clamp. The outlet side of the valve is glued to the Y I replaced all the outlet piping. A rebuild would save that trouble and expense. But if the slide or the valve body is cracked or warped there is no rebuild.

This might be obvious. You would really like to get that valve open somehow before you take the system apart.

Actually I have a new valve I forgot about and am lookin at it. I decided to just keep it as a spare. Maybe I bought it for that. It is likely that the rod is broken from the plastic slide. No, I do not think it can be re attached if that is the case. I do not really want to open this package to take the valve apart to see. Valve says $67.95 on the package.

groundhogy 06-27-2020 03:58 PM

So i ran my scope camera up the hole to take a look and verify what the “tech” told me. He said, after a mighty mighty try, he could not get his little hose past my black tank gate..

I can see it opening and closing.

CRH 06-27-2020 04:19 PM

If your valves haven't been replaced, you are probably on borrowed time, anyway. I replaced both of mine. All the parts were about $170. The job wasn't all that difficult.

Mollysdad 06-27-2020 05:01 PM


Originally Posted by groundhogy (Post 2376423)
So i ran my scope camera up the hole to take a look and verify what the tech told me. He said, after a mighty mighty try, he could not get his little hose past my black tank gate..

I can see it opening and closing.

I'm getting conflicting information. If you see the gate opening and closing, with an endoscope, I'd run a garden hose in the window into the toilet and fill the black tank with water. Then work the valve and see what comes out. Since you saw the poop pyramid, it may be that your tank monitor has some paper on it and is giving you an erroneous reading. It's also possible you have a blockage right at the gate valve also.
I'd try the simple stuff first, before surgery.

groundhogy 06-27-2020 05:12 PM

CRH, if only my life were that uncrowded (like it used to be), i will just switch back to the other 20 emergencies i was already dealing with.

MollysDad, yes, i see what you are saying. The guy at the RV store has some magic jug of stuff that will dissolve the great pyramid. I will get that monday and resume to fill with liquid. Then attempt to dump again. We dont put TP down the hole so its not that.

We never had much problems before. Recently the half ball flusher stopped moving when flush pedal was depressed. So for several weeks I had locking pliers on the half ball axle. We flushed by turning that.
I think not enough flush water was going in which started the pyramid building.

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