Thetford Drain Valve - Blackwater

[JHBurns100]

The Thetford Blackwater drain valve on my 24foot 1978 Argosy has cracked and allowed sufficient movement that the connection is leaking. The gray water valve appears to be fine, and also appears to be glued in place, there are no large screws in the valve housing.
It appears that I may need to remove the whole drain assembly which will be a large problem. Does anyone know if the blackwater valve can be replaced without removing the complete assembly? Any and all suggestions on how to handle this problem would be extremely welcome!
The trailer serviceman to whom I spoke said it is all glued together and would cost $400 to $450 to install the new blackwater valve. I brought the trailer home, and thus far I have removed the rivets on the pan between the rear bumper and the belly pan. I pulled out the pan holding the electric wire and drain pipe.
Thank you, Jim Burns

[ViewRVs]

If the bonded side is not cracked, you have two options. Only one side is bonded to the pipe. The other should have screws in the side that holds the two sides together.

1) Get a new seal kit. Take it apart and put in new seals.

2) Get a new valve and replace everything but the part bonded to the pipe.

Maybe your valve is different than mine.

[wayner1239]

I bought a new valve for mine and was able to install it without too much trouble. I took the bolts out and was able to spread the valve holder apart just enough to slide the new one in. I had to try it a couple of times because the space was so tight that the seals were knocked out of place on the first try. (Sorry I cannot describe the procedure better - it has been a couple of years and I cannot remember exactly what was involved.)
Yours may be different from mine. One other option for me would have been to hacksaw the pipe at the bottom of the tank and replace the whole assembly. Good luck.
Wayne

[femuse]

Just to encourage you: we successfully replaced that valve on a 1974, which may be closer in installation to yours.

[rwewed]

I am new to the forum and can't figure out how to start a new thread. So i am replying to this similar thread.

Does anyone know how to tell what Thetford model # 014447 valve one has without diassembling it. I understand all of their valves are model# 014447 but are still different. There is a patent number visible. Is that distinct to my particular valve.

Robert

[Inland RV Center, In]

Originally Posted by omnistream

I am new to the forum and can't figure out how to start a new thread. So i am replying to this similar thread.

Does anyone know how to tell what Thetford model # 014447 valve one has without diassembling it. I understand all of their valves are model# 014447 but are still different. There is a patent number visible. Is that distinct to my particular valve.

Robert

No. That number is on all the valves.

You can determine what valve you have by looking at the photo's of the different Thetford valves that are still available.

We have all of them listed in the parts sale section of our web site, Airstream Parts Sale Inland RV Center, Inc. (951) 734-8130

Andy

[Lumatic]

I just did mine on my 71. It was not as bad as I thought it would be. I don't know about yours but on mine the valve is bolted into a fitting that is attached to the black water tank. below the valve is a connector T the grey water feeds into. This was the only glued connection. I semi permanently glued on a Valterra Universal Adapter to the Thetford sewer hose connection with vulkem so I could use Valterra connections for the hose.

[rwewed]

What are they (thetford) thinking? They sure could make life easier if they just specified with visible numbers for each variation. BUT, I broke down and went ahead and took mine apart.
Broke it trying to remove it from from the 90 elbow, (some smart fellow had glued it in there) so now my system is unusable (no fun being a full-timer) but went on Inland RV website and found what I needed. Have two coming overnight Thanks ANDY! You guys have come through for me twice now with odd things that I need!

Robert.

[jbsails]

I am going through a similar situation on my Argosy 1973 20' trailer. I had to grind off the Thetford slice valve because the four screws were severely rusted. There appears to be a permanently mounted white flange that is affixed to the bottom of my holding tank and the four rusted screws hold the slice valve which affixes to this flange.

Now the rusted screw studs remain in the holes for this flange...making a simple "bolt on the new thetford slice valve" into a bit of a nightmare...drat!!!

Now that I have a Margarita in front of me...life is better (I make a mean margarita if I do say so, myself...and obviously I have passed the "get a beer" recommendation that Andy of Inland RV often recommends...but I digress)

....do I now have to drill out those studs??? ...and re-tap??? Never done that before.

Is there any way to replace/remove the fitting that appears to be permanently affixed to the bottom of the holding tank??

Should I go to plan "B" and pour another margarita??

[azfiredog300]

Spray the rusted bolts with WD40 and let them soak for a while. Then hook some vice grips on them and they should come out pretty easily.

[rwewed]

Originally Posted by jbsails

I am going through a similar situation on my Argosy 1973 20' trailer. I had to grind off the Thetford slice valve because the four screws were severely rusted. There appears to be a permanently mounted white flange that is affixed to the bottom of my holding tank and the four rusted screws hold the slice valve which affixes to this flange.

Now the rusted screw studs remain in the holes for this flange...making a simple "bolt on the new thetford slice valve" into a bit of a nightmare...drat!!!

Now that I have a Margarita in front of me...life is better (I make a mean margarita if I do say so, myself...and obviously I have passed the "get a beer" recommendation that Andy of Inland RV often recommends...but I digress)

....do I now have to drill out those studs??? ...and re-tap??? Never done that before.

Is there any way to replace/remove the fitting that appears to be permanently affixed to the bottom of the holding tank??

Should I go to plan "B" and pour another margarita??

I sympathize with you. You may have 'screwed the pooch' so to speak by grinding off the heads of the bolts. They are only threaded into plastic so they ought to be able to be backed out with a backing bit. Then you will probably have to replace the valve AND the piping that the valve is glued to. Thetford ought to be ashamed of themselves and Airstream as well. To use a system that requires replacement of one part with two that has to be TOTALLY replaced instead of rebuilt ( with seals only) should be a crime. Of course I am finding that the entire RV industry (Airstream included) has a major engineering deficit. It's like every item is installed with no thought whatsoever to the need for maintenence or repair in the future. They just slap the stuff together and sell it. DAMN, now I need a margarita!
Rob

[Pick]

Thetford ought to be ashamed of themselves and Airstream as well. To use a system that requires replacement of one part with two that has to be TOTALLY replaced instead of rebuilt ( with seals only) should be a crime.

I think it is a very good system, if installed properly. I just replaced my drain valve without much trouble. Yeah, those screws holding the valve in can be trouble if rusted and my two bottom ones were. But if you have the right bit or screwdriver, that makes all the difference in the world. Mine had been replaced once or twice before and the last time they put everything back together with rubber couplings and hose clamps. I did not have to cut anything. It also looks like the piece attached to the tank had a hose clamp on it, so it might have been attached without gluing. The old valve had a badly rusted shaft on the pull rod and after removing the valve, I saw the gate itself had a layer of rust on it. It also leaked.

[Gkiesel]

Originally Posted by Pick

I think it is a very good system, if installed properly. I just replaced my drain valve without much trouble. Yeah, those screws holding the valve in can be trouble if rusted and my two bottom ones were. But if you have the right bit or screwdriver, that makes all the difference in the world. Mine had been replaced once or twice before and the last time they put everything back together with rubber couplings and hose clamps. I did not have to cut anything. It also looks like the piece attached to the tank had a hose clamp on it, so it might have been attached without gluing. The old valve had a badly rusted shaft on the pull rod and after removing the valve, I saw the gate itself had a layer of rust on it. It also leaked.

Pick, It seems very inconsistent. Our 76 Argosy was completly glued together, which required cutting and making all new when the valves needed replacing. It's not supposed to be completly glued but our trailer sure was.

[rwewed]

Pick, It is a "good system" in that it works well. I too have the rubber couping and hose clamps to connect the elbow and I replaced my screws with stainless steel screws (duh! why didn't Airstream do that to begin with?). However the valve was glued to the elbow. So, I stand by my comment that having to replace two full components (the valve and elbow) when only the seals on the valve are bad is poor engineering at best and just dirty selling of unneccesary parts at worst. I tend to think it is the latter.

[blickcd]

I know this thread is a few months old but I had to comment on my experience with a broken dump valve.

For me the part that was broken was the square frame piece that is glued onto the outlet of the black tank. Two of the corners that the valve screws go into had broken loose, but were still there hanging onto the screws. That left enough slack in the system to cause a slow drip when the black tank was nearly full.

When replacing both valves, which had leaky internal seals, I was able to repair the broken frame so it could be left in place and reused. I just cleaned both edges of the breaks very well, roughed them up with some fine sandpaper, and then stuck everything back together with some solvent glue that was rated for ABS and PVC pipe. Just to be sure, I let that joint cure for over an hour before reassembling everything.

That was several years ago and no problems since.

Christopher

[tfbeitz]

Thetford Valve sealant/lubrication
In reassembling thr Black water ank Valve and Discharge, I would usually use vaseline to coat the rubber gasket. I vaguely recall being told "DO NOT USE Vaseline"

Any suggestions
Thanks