Thetford dump valve gaskets

[nickclifford]

Hi all .. question on dump valves on my '76 Argosy. Both were jammed. Managed to gain access via belly pan removal and opened up the valves. Both now sliding again. Vintage Trailer is out of the gasket repair kits... I'm thinking for now, while I wait, patch up by making my own gasket ... anyone ever repaired these ? would love to hear your thoughts ... I want to have the traier operable for now. Can go back in and repair with new seals etc when available.

[crispyboy]

How about this?
https://odmrv.com/catalog/index.php?...tq53g9fk30h3u4

[Bill M.]

I have repaired valves and have replaced valves. My suggestion is to just buy 2 new valves and the plumbing and replace the whole system. The body of the valves weakens with time. Mine eventually "crumpled" and they were not as old as yours. You have the hard work done with cutting the access panel. I would also end up with the newer Valeria connection on the outlet pipe. I do not know whether it was a bad idea or not but because of time and supply and cost issues I used PVC pipe instead of ABS when I did mine a few years ago and it has held up fine.

[ROBERT CROSS]

Originally Posted by Bill M.

I have repaired valves and have replaced valves. My suggestion is to just buy 2 new valves and the plumbing and replace the whole system. The body of the valves weakens with time. Mine eventually "crumpled" and they were not as old as yours. You have the hard work done with cutting the access panel. I would also end up with the newer Valeria connection on the outlet pipe. I do not know whether it was a bad idea or not but because of time and supply and cost issues I used PVC pipe instead of ABS when I did mine a few years ago and it has held up fine.

What he said...

Bob
🇺🇸

[nvestysly]

I repaired mine once about 10 years ago (actually, the Airstream service center did the work) and I was never happy with the results. When I finally decided to do the repair myself, I decided on replacing the entire valve body for both gray and black tanks. Couldn't be happier!

I'm including two links below but these are for reference only. Valve designs vary. Be sure to determine the type of valve that is designed for your RV.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

https://odmrv.com/catalog/index.php?...oducts_id=1590

[richard5933]

I'll add one more voice to the "replace them" crowd. The plastic gets more brittle with age. You can rebuild them, but if they are more than a few years old it's an illusion to think that this will save you time/money. In the end you'll likely be doing it again and replacing the valves so you might as well do it now. I rebuilt one of mine and kept it as an emergency spare. If one of the new ones fails at least I can swap it out quickly and carry on until another new one can be found.

[nickclifford]

thanks for suggestions, prob makes sense, I was hoping to avoid replacing the pipe but may as well go for it ...

[overlander64]

It looks like I may be a lone dissenter on this issue, but even if I were to replace the entire valve assembly, I would still go with the Thetford. The Thetford components may be a little more costly, but my experience has been that they far outlast the Valtera products. Currently, I have Thetford on my 1964 Airstream Overlander Land Yacht International and Valtera on my 1978 Argosy Minuet 6.0 Metre. The valve on my Overlander has had to be rebuilt periodically, but the only time that I have had to replace it was when the black tank was high centered on a driveway slope resulting in damage to both tank and valve. I have never had to replace the Thetford connector for my hose or the outlet cover, but I did have to buy a cover with the garden hose adapter when I purchased the trailer in 1995 as the second owners had only used a solid cover. The first owner of my Minuet converted it to Valtera prior to my purchase in 2003, and I have had to have its valve replaced five times during the intervening years and the hose connectors and outlet covers do well to last through two or at most three seasons of use. Converting the Minuet back to Thetford is on my list of things to do when time permits.

[Bill M.]

I meant go with the Tetford valves but use a Valtera connection for the dump hose to make life easy. The Tetford valves are great. The Tetford connector is better also but hard to buy hose for off the shelf.

[jimfa440]

Work on it once, replace it.

[1970 Safari]

Sorry to hijack the thread but the last post caught my attention....
I use Thetford and have a hard time finding proper sized hoses to use with the ends. All the ones I have found are slightly small to "no way" will it fit. Where can Thetford sized hoses be purchased?

[azflycaster]

Just use one of these...
https://www.amazon.com/Valterra-T05-...a-524448817405

[overlander64]

Originally Posted by 1970 Safari

Sorry to hijack the thread but the last post caught my attention....
I use Thetford and have a hard time finding proper sized hoses to use with the ends. All the ones I have found are slightly small to "no way" will it fit. Where can Thetford sized hoses be purchased?

I found my 3.5" hose at Home Depot, see: Valtera EZ Flush Premium RV Drain Hose Super Heavy Duty.

Genuine Thetford hoses can be found on Amazon, see: Thetford 70422 Sani-Con 35' Sewer Hose

I have found that I can often find a 3.5 inch hose at one of the big box stores in my area, but I need to take a tape measure to check diameters as there are so many that are only 3.0 inches. My local non-Airstream RV dealer also stocks 3.5 inch heavy duty hoses in their accessory shop.

[nickclifford]

Originally Posted by 1970 Safari

Sorry to hijack the thread but the last post caught my attention....
I use Thetford and have a hard time finding proper sized hoses to use with the ends. All the ones I have found are slightly small to "no way" will it fit. Where can Thetford sized hoses be purchased?

I bought a hose off amazon, and a VERY tight fit .. took serious strength to tighten on ...

[Bill M.]

"I bought a hose off amazon, and a VERY tight fit .. took serious strength to tighten on ..."

One reason to like the Rhino flex hose with the Valtera connection adaptor. They have little levers (like wrenches) to use if it is too tight or stuck. You can stick the adaptor on with silicone.

[wrhnco68]

I finally gutted up, cut the hole in the pan and got to work. The process is no fun but easier for being forewarned. In particular, the advice to use "z-channel" to use instead of just slapping a patch on, is a great suggestion for us "over-doers". I didn't anticipate the problems with the availability of ABS pipe and fittings. I ended up buying almost everything from Amazon. I'm wondering if I should order another set of everything just in case.

A quick note. When I had finished with "wet-testing", I was left with both tanks with closed valves but partially full while I buttoned up below. Instead of the rivet that held the valve extension on the Thetford valse shaft, I decided to use a stainless cotter pin. While I was trying to get the pin for the black tank in place, I managed to bump the new, greased valve to the black tank. Those work clothes are now drying out in the barn. I apologize to any neighbors who might have seen my rush to the shower.

[richard5933]

Originally Posted by wrhnco68

I finally gutted up, cut the hole in the pan and got to work. The process is no fun but easier for being forewarned. In particular, the advice to use "z-channel" to use instead of just slapping a patch on, is a great suggestion for us "over-doers". I didn't anticipate the problems with the availability of ABS pipe and fittings. I ended up buying almost everything from Amazon. I'm wondering if I should order another set of everything just in case.

A quick note. When I had finished with "wet-testing", I was left with both tanks with closed valves but partially full while I buttoned up below. Instead of the rivet that held the valve extension on the Thetford valse shaft, I decided to use a stainless cotter pin. While I was trying to get the pin for the black tank in place, I managed to bump the new, greased valve to the black tank. Those work clothes are now drying out in the barn. I apologize to any neighbors who might have seen my rush to the shower.

Great news that you got it done, and yes, the z-channel is a great addition to the project and makes for a very neat finish.

ABS is not legal in all jurisdictions for household plumbing, so it's not sold everywhere. I had to drive halfway across Wisconsin to find it. It's possible to use PVC with a little creativity and the proper glue, but the curves of the PVC don't match the OEM pipe exactly and can create problems. I found it easier to drive three hours than to modify the plumbing layout.