'62 Flying Cloud Dump Valve Rebuild

[Andrew M. Franklin]

My black water dump valve started leaking 1/2 qt./day. This valve may be original to the trailer and my understanding is that Thetford valves were used back in '62. There is a cast brass gate that slides into a machined groove in the housing. It is a little sticky, but will go in all the way by hand - nests approx. 1/8-3/32" into the groove when fully closed. I assume it is closing all the way. I blew water and compressed air into the groove in case there was something interfering. Also lubricated it with wd-40. Assumed that couldn't hurt anything. Still has a slow leak. Can this valve be rebuilt/resealed? Does anyone have experience doing this? Where can parts be purchased? Thanks. Sincerely, Andy

[Lotek]

Hey Andy,

I have the old bronze dump valve too. You can rebuild them.

After you remove it and take it apart, it is pretty self explanatory. After you clean up everything there are only two things that can be wrong.There is an O ring that the sliding gate valve seats against. It may have deteriorated, or shrunk. The gate valve may also be scored. If you take it to an O ring supplier, they should be able to match it up. You can smooth out the gate valve enough to get a seal with the new O ring.

It took me a while to locate an o ring that was the proper thickness and resliliency.

When I was finished, I replaced all the nuts & bolts with stainless.

Mine doesn't leak a drop now.

Good luck!

[Andrew M. Franklin]

Thanks for the post, Courtney. Got the old valve off and it turns out that the gasket between the valve body halves dried out. It was not leaking at the "O" ring like I thought... Had to fill the tank and spray compressed air all around the valve till I figured out that leak was coming from casting mating surface. Bolt heads were fluffy rusty crustletts that I ground off. Then carefully split the casting halves. Then had little stumps I could grab with vise-grips to unscrew "top" half of valve casting from tank. They were VERY tight, so I carefully heated the bosses with a torch and they came out fine. Now I have it on the bench and am ready to rebuild. "O" rings shouldn't be a problem to match up somewhere. But I have 2 questions: THere seems to be a green "finish" applied to the gate where it contacts the O ring. Most of it is worn off, but seems to provide a smooth surface for O ring contact. Anyone else seen this? Should I simply polish the gate? Also - valve body gasket is dust. I was thinking of using RTV caulk. Any ideas? Thanks. Sincerely, Andy