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08-02-2008, 08:59 PM
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#1
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3 Rivet Member
1972 23' Safari
Dearborn
, Michigan
Join Date: May 2007
Posts: 120
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Thetford Valve Installation
I am just not winning my battle with the black water tank.
I have the new tank and the valve installed. Currently I am reusing the Thetford valve which came off of the old tank. The valve was brand new back in January when the dealer tried to repair the old tank.
So I filled tank up to almost the top with water, and it drips (just a little bit but it drips). The water is forming on the top of the valve towards the handle and then dripping over the sides. So I am assuming that it is leaking between the valve seal and the tank.
I took it back apart and I found that there was just a little bit of resin on two of the screw posts on the tank (fiberglass tank - valve mount came pre-installed). So I carefully scraped off the resin so now all 4 posts are clean at the mating surfaces between the valve and the tank. There doesn't appear to be any resin on the seal surface so everything is OK there.
When I put it back together, it didn't leak quite as much (instead of seeing a puddle as soon as I turned off the water, it took a minute or two for it to form).
I noticed that the valve has some red waxy material that appears to have been put on the seal to help it work better. Most of this has been wiped away, particularly on the rubber seal. The rubber seal looks fine, I can't find any tears or cracks in it and it doesn't appear to be deformed any any way.
I am about to order a new valve but I am concerned about going back down the same path again.
Has anyone else fought this battle and won? Is filling the tank almost to the top a valid test? Is there something I should put on the seal to make it work better?
I could take the tank back out and reattach the valve and try filling it up with water so I can get a better look at the problem ... but I am concerned about supporting the tank adequately so I don't damage it with all that water in it. I will also have to take the valve off when I reinstall the tank.
Any suggestions?
Tom Bray
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08-02-2008, 09:04 PM
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#2
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Retired.
Currently Looking...
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, At Large
Join Date: Jun 2003
Posts: 21,276
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First suggestion: Wait.
Leave the termination cap on the outlet for the sewer, and let the tank sit full of water for a day. Slide the valve up and down several times. Then make sure it's closed, and remove the termination cap. After the water that's in the pipe comes gushing out, you may find the drip has stopped.
__________________
Meddle not in the affairs of dragons, for you are crunchy, and taste good with ketchup.
Terry
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08-02-2008, 09:25 PM
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#3
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3 Rivet Member
1972 23' Safari
Dearborn
, Michigan
Join Date: May 2007
Posts: 120
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If the inside of the valve were leaking that would be different. The water is going around the outside of the valve and is sitting on the top of it.
I may try your idea to see if things will set up over night. Both times I got frustrated after about 10 minutes and pulled the plug.
Tom Bray
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08-03-2008, 06:39 AM
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#4
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Retired.
Currently Looking...
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, At Large
Join Date: Jun 2003
Posts: 21,276
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Quote:
Originally Posted by Tom Bray
If the inside of the valve were leaking that would be different. The water is going around the outside of the valve and is sitting on the top of it.
I may try your idea to see if things will set up over night. Both times I got frustrated after about 10 minutes and pulled the plug.
Tom Bray
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Patience, Grasshopper. The black tank dump valve leaked a little on our Overlander right after I installed it. It stopped leaking after the second trip, and AFAIK has not leaked since, even after the people that bought it from us dragged the fitting off it on a curb.
__________________
Meddle not in the affairs of dragons, for you are crunchy, and taste good with ketchup.
Terry
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08-03-2008, 02:22 PM
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#5
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Rivet Master
1967 26' Overlander
Huntsville
, Alabama
Join Date: Dec 2003
Posts: 3,018
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Stay the course
Quote:
Originally Posted by Tom Bray
... I am about to order a new valve but I am concerned about going back down the same path again. ... Any suggestions?
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Okay, so the existing valve is currently not perfect. Yes, everyone would prefer it had an absolute seal. It might fix itself (rubber seals are funny that way) or it might not.
But if you are running Airstream's original design for '72 (no built-in gray tank), then you are supposed to be toting a tank on wheels to hold gray water. An occaisional drip from the black tank into to the tote tank won't smell or hurt anything. If you're not totin' a tank, then an occaisional drop of black mixed with gray drained on the ground is still not going to be a problem.
Go camp a few times & keep an eye on it. If, after a few trips, you don't like the leak rate then gear up & replace the valve.
Tom
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08-03-2008, 02:49 PM
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#6
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3 Rivet Member
1972 23' Safari
Dearborn
, Michigan
Join Date: May 2007
Posts: 120
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So what I am hearing is, put it back together and see how it does.
For the time being I will leave the piece of aluminum under the valve off so that it can drip onto the ground for the time being. I also have to make sure everything is empty before I put it back in the barn.
Yes I have a tote ... we also added limited storage in the pipes ... there are two sections of 3" pipe for the bathroom and kitchen drains to store a little bit of gray water. I have added extra valves so that I can control the storage. I have tested these and they don't seem to leak, at least on the outside of the valves.
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09-03-2008, 09:31 PM
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#7
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3 Rivet Member
1972 23' Safari
Dearborn
, Michigan
Join Date: May 2007
Posts: 120
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I finally have enough of the trailer back together so I could drag it out into the weather and play with filling up the blackwater tank (for that matter all the other plumbing systems were tested this weekend too).
I filled up the blackwater tank so that the half full indicator came on and watched it drip on the ground for about 3 days. I was surprised to see that on Monday afternoon there were only occasional drips.
Due to the uncertain weather, I put the AS back in the barn Monday night. There were a couple of drips right after I moved it but these evaporated and I haven't seen any water on the floor since.
Now the question is, do I need to keep water or the toilet chemicals in the tank all the time to keep it from starting to drip again?
What is the right amount of fluid to leave in the tank when it isn't being used?
I have the belly pan removed around the drain area which I want to re-install. The dealer when they put it back together put caulk all around the drain so no water got in but it couldn't get out either.
Should I leave a space around the drain where it comes through the belly pan and not make it real water tight so if things drip in the future there is someplace for it to drain out to?
Thanks
Tom Bray
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09-04-2008, 07:11 AM
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#8
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3 Rivet Member
2010 28' Flying Cloud
Escondido
, California
Join Date: Feb 2007
Posts: 196
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I would try removeing the valve and coating the mating surfaces with with non harding permatex gasket sealer and reinstalling.
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09-07-2008, 08:57 AM
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#9
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3 Rivet Member
1972 23' Safari
Dearborn
, Michigan
Join Date: May 2007
Posts: 120
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When the valve was originally installed on the old tank it had this red stuff on it which I haven't been able to identify. If anyone has a clue it would be helpful.
Of course I don't know if it helped at all since the old tank was leaking from around the same general area ... I blamed the tank since the dealer said they had tested it when they put it back together.
I am reluctant to take it back apart now that it is behaving. I haven't seen any evidence of leaking in a week now.
Tom Bray
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