Dump Valve First Aid?

[tonyseidel]

My '66 Caravel dump valve is leaking when closed. I've flushed the tank with cold water to no avail; sprayed the pull-lever w/WD-40. What can I pour in the tank and let the seals soak without harming them? Thinking of soapy water, household drain cleaner (?); someone suggested cooking oil???

[pappy19]

I have the same problem on my 2002 Classic, when I open up the main cap, I am getting some stinky liquid when both of the valves are shut tight. I was thinking I may need to replace mine one of these days, but if the seals can be rejuvinated, that would be nice.

[Alumaholic]

Camco makes an additive to add to the holding tanks once a year to lubricate the valves. It's formulation includes coconut oil.
It really isn't a seal replacement issue as much as a "clean-the-pooh-out-of-the-valve" issue. Since it's just a big, sliding-gate valve; pooh and paper get jammed into the grooves and prevent the sliding gate from closing all the way.
It helps to run a tank full of water (with a bottle of fabric softener and some detergent) through from time to time while you manipulate the valve open-close, open-close, open-close, etc. Until you get the crud out.
Then add the coconut oil lubricant per instructions.
Hope this helps!

[r carl]

Originally Posted by sierratony

My '66 Caravel dump valve is leaking when closed. I've flushed the tank with cold water to no avail; sprayed the pull-lever w/WD-40. What can I pour in the tank and let the seals soak without harming them? Thinking of soapy water, household drain cleaner (?); someone suggested cooking oil???

I would try filling the dump tank with water and lots of dish soap, then during dumping, work the valve open and shut several times to lubricate and clean it.

[77 R GO C MH]

....and if/when all this fails, you could replace the valve(s). This can be quite involved and expensive. OR another option is to purchase a Valterra twist-on waste valve that attaches to bayonette connection on the end of your dump outlet (where the "slinky" hose connects). This will stem the leakage and is quite inexpensive....about $20.

[Wazbro]

Something that worked on my trailer, get a rubber mallet ($3 Harbor Freight) and give the pull valve a couple LIGHT* taps while it's closed.

*LIGHT means no harder then you would want to hit your hand a few times.

[Cristobal]

I'm new to all this but I noticed on mine that it looks like someone used a wax ring from a toilet bowl seal to lube mine.

[pappy19]

I just bought the Valterra Twist On Valve for $18.50 from Amazon. Can't be much more simple than that for a fix. Thanks for the heads up.

Pap

[tonyseidel]

Thanks to all for the ideas. I'll try the soap/oil and mallet treatments before I buy a Valterra add-on valve, (which sounds like a great alternative to a rebuild!).

Tony in Sonora, CA

[Bill M.]

Repairing the valve is a $500 job at Jackson Center. Camping world one location quoted $500, another $1000. The Valterra is cheap by comparison. But I did not like it much. Worried about how much it stuck out and I could not find a good way to orient the handle so I could open it. Finally crawled under the trailer and did the vave. Took me one half day to cut the hole in the pan and one half day to do the valve. A couple of more hours to button up the hole.

[tonyseidel]

The Valterra T-58 twist-on valve says it's 3-inch. What does this refer to? My '66 has the original Thetford sewer connector, and it's larger than 3-inch diameter. I'm told the "newer" Thetfords are different. I know when I buy a cap for it I have to specify it's the "older" style. I'm afraid the Valterra won't fit...

[tonyseidel]

I've learned that the Thetford waste valve to Valterra fittings adapter (part no. T05-2285VP avail. on Amazon or Vintage Trlr. Supply) WILL fit the old Thetford size 3.5" and reduce it to the Valterra 3.0" - so the twist-on Valterra (T-58) dump valve can be used. Unfortunately I've figured out that my problem isn't the valve itself but somewhere above (fun, fun) the valve. To be continued...

[tonyseidel]

Well, the old plastic tank was cracked on top and bottom - the original Thetford valve was ok. So, my '66 Caravel now has a new exact replacement fiberglass tank AND valve. In and out thru the bottom of the closet, by the way, leaving the shower pan intact. Thought about the Valterra twist-on valve momentarily and then realized it also shuts off the grey water drain.

[Protagonist]

Originally Posted by sierratony

My '66 Caravel dump valve is leaking when closed. I've flushed the tank with cold water to no avail; sprayed the pull-lever w/WD-40. What can I pour in the tank and let the seals soak without harming them? Thinking of soapy water, household drain cleaner (?); someone suggested cooking oil???

Not knowing if the valve seals are original or if they've been replaced, all I can say is that all rubber compounds eventually harden and crack over time, beyond the ability of any lubrication or treatment to fix.

But if you want to try restoring your existing rubber seals, there are a couple of ways, but they're only temporary fixes. Decrepitude of the rubber will eventually defeat anything you try:

If you can't remove the seal, the best treatment to use is ordinary household ammonia. Mix the ammonia with warm water, fill the tank, and let it sit for a couple of hours, then drain.

If you can remove the seal, clean the seal first, with a pot-scrubber sponge, heat the seal in boiling water to soften it, then remove it from the water and apply glycerine to the hot seal using a cotton swab.

I've read somewhere about people using lye soap to restore flexibility in rubber, but that's even nastier to handle than ammonia, so I've never tried it. Plus it takes longer; from what I've read, you'd have to soak the rubber in the soapy water for about ten days to get the same effect as two hours with ammonia.

Side note, the ammonia and glycerine treatments would work equally well on rubber window weatherstripping, which is where I first picked up these techniques, restoring an old house.

[airdreamers]

Originally Posted by 77 R GO C MH

....and if/when all this fails, you could replace the valve(s). This can be quite involved and expensive. OR another option is to purchase a Valterra twist-on waste valve that attaches to bayonette connection on the end of your dump outlet (where the "slinky" hose connects). This will stem the leakage and is quite inexpensive....about $20.

I was doing my every other month walk through my local RV dealer not knowing if or what I wanted to buy for my AS. You never know what's on sale or an idea hits you to correct a problem. Well if I read this thread when it was started I would bought this valve months ago. Thanks for the tip.