Drain valve lubrication with Silicone spray

gordonsick · 09-04-2016, 09:10 PM

Pardon me if this has been discussed already. But, a quick search on the forums only led to discussions of using chemicals (Thetford, Camco, etc) in the grey and black water tanks to lubricate the drain valves. I have a solution that is simpler in many respects, because it doesn't require you to have a plan on when the tank will be empty enough to add and empty the lubricant.

My solution is shown in the photo below.

I drilled and tapped a 1/8" pipe thread into the top of the plastic housing above the drain valve slider and installed a 1/8" brass plug (plastic is ideal if you can find it). It is finger tight. The proper drill bit for a 1/8" pipe thread is 21/64", which is a rare bit, but you can easily use a 5/16" bit, since it is plastic.

When I open the drain valves, the valve faces are in the panel below the drain plugs. I spray silicone spray into the holes, which lubricates both sides of the valve slide, as well as the push-pull rod. It works well. And, I can use it any time that I have opened the valve.

Obviously, you don't need food-grade silicone spray, but I carry it with me to lubricate the O-rings and threads for my water filters. You can get it at a shop that sells equipment for making sausages (e.g. go to a hunting supply store).

trbomax · 09-04-2016, 09:20 PM

I hope you use a different tube on the nozzel for the water filters.........

gordonsick · 09-04-2016, 11:19 PM

That's a good point. Sanitation is an important issue and I did spend a lot of time thinking through the sanitation issues when designing this. That planning was useful, because this design doesn't create a sanitation problem.

The following points are germane to this issue:

- The Silicone spray that I have does not have a tube to direct the spray. Since the hole I drilled is quite large and the spray is quite directional, I'm not in contact with the dump valve when I spray. If that was an issue, I'd use another Silicone spray can that I have, which isn't food grade, but which stays at home.

- There is no evidence that sewage gets into the flat plastic body into which the valve handle fits – which is where I'm spraying. It seems that the seals that prevent the dump valve from leaking also wipe the valve before it comes out into that plastic body body. If sewage was getting into that plastic body, I'd expect to see it leaking out around the rod that runs the valve, or out of the bottom of the plastic body itself, since it seems to be just snapped together, with no effort at sealing against leaks.

- When planning this, I put the brass plug high, so that any sewage that got into the plastic body would fall and sit below the plug.

- The brass plug is on a pipe thread, and I can use standard Teflon tape or whatever to make sure that the plug is well sealed and not leaking outside of the assembly when I'm finished my lubrication job.

- I don't remove the brass plugs until I've finished dumping the tanks, so there is no significant sewage flow going through when I do the spraying.

–Gordon

Bear fans · 09-05-2016, 02:42 AM

I'm pretty white lithium grease is recommended for lubing the waste valves

Carrier · 09-05-2016, 09:12 AM

So does it stop sticking hard to open/close valves? Will have to try it as all three of mine are getting stiff.

gordonsick · 09-05-2016, 11:02 AM

The advantage of my solution over grease is that you would have trouble reaching into the valve cavity to get lithium grease in there. You would want to be sure that the lithium grease isn't petroleum based.

The lubricant really made my valve easier to operate and it was getting stiff. I did this after I did a Thetford lubricant treatment. The Thetford helped, but the silicone spray made it smooth as new.

Another advantage of my system is that if the valve is really sticky, you can install the hole and plug and spray in the silicone and let it sit for a while. It would drip down over both sides of half of the valve. That might be enough to let you open the valve without breaking it. If it was really stuck, I'd try the chemicals in the tank at the same time.

fella10 · 09-05-2016, 01:01 PM

Quote:

Originally Posted by gordonsick

When I open the drain valves, the valve faces are in the panel below the drain plugs. I spray silicone spray into the holes, which lubricates both sides of the valve slide, as well as the push-pull rod. It works well. And, I can use it any time that I have opened the valve.

IMO that's a good idea, thanks for posting it,...... it seems like using the little straw that comes with the silicone spray would help get the silicone into the cavity better,.... seems like with it you could actually spray one side then pull it out and stick it back in on the other side of the slide,..... if its not such a tight fit of the slide in the cavity that you can't get the straw in there,... anyway, I get to do another mod......

labarn · 09-05-2016, 02:50 PM

we have the pull and push valve. when it gets harder to use I drain the tank. Pour one gallon of vegetable oil down the toilet. let is sit for as long as you can and then I quickly pull and push back and forth. works great for maybe a winter season plus. I have done this several times with the same result.
labarn

gordonsick · 09-05-2016, 09:07 PM

Fella,
My silicone spray can has a very focussed spray, so there was very little waste going into the hole that I drilled, even though I was spraying without a straw tube and from a distance of 1 or 2 cm. The actual valve mechanism is so far from the hole that spraying through the hole results in the spray going all over inside the cavity. I didn't have to sweep from one side to the other.

The idea of vegetable oil is interesting and I can see that it might work nicely. My black water valve was tighter than the grey water valve. And the grey water valve may have had some oil an soap behind it that made it slippery.

-Gordon

northstar1960 · 09-05-2016, 09:25 PM

Quote:

Originally Posted by gordonsick

Fella,
My silicone spray can has a very focussed spray, so there was very little waste going into the hole that I drilled, even though I was spraying without a straw tube and from a distance of 1 or 2 cm. The actual valve mechanism is so far from the hole that spraying through the hole results in the spray going all over inside the cavity. I didn't have to sweep from one side to the other.

The idea of vegetable oil is interesting and I can see that it might work nicely. My black water valve was tighter than the grey water valve. And the grey water valve may have had some oil an soap behind it that made it slippery.

after looking again . wouldn't all the silicone get wiped off before it even touched 70% of the seals

-Gordon

Good idea ! looks like you really don't even need the brass plugs . if the seals are leaking it would come out where the handle enters the housing . this way you'll have a weep hole to let you know when to replace the seals

fella10 · 09-05-2016, 09:55 PM

Quote:

Originally Posted by northstar1960

Good idea ! looks like you really don't even need the brass plugs . if the seals are leaking it would come out where the handle enters the housing . this way you'll have a weep hole to let you know when to replace the seals

in our area, an open hole like that would be an "invite" to the mud daubers to "come on in",...... around here, they'll stop up any hole they can find,..... I believe if I'm going to use the straw to spray into the cavity, I can actually do this mod with a much smaller hole and then close it up with a small screw,....

otisite2016 · 09-06-2016, 09:46 AM

Thats a great idea Gordonsick.My black water is tough to work so will try that. Thanks

Dave Lyon · 09-06-2016, 10:19 AM

I recently tried the Thetford valve lubricant......waste of money.

I used silicone spray and it worked perfectly.

fella10 · 09-09-2016, 01:59 PM

Gordonsick,

I did the mod and am pleased with the results, thanks for your post,....

Wolverine 1945 · 09-10-2016, 10:34 AM

White Lithium comes in spray can !!!

gordonsick · 09-11-2016, 05:18 PM

When I googled White Lithium spray, I found a WD-40 White Lithium product. Standard WD-40 is petroleum based and cold damage the drain valve seals if they are rubber-based.

Unless I had clear evidence that the WD-40 White Lithium is not petroleum based, or that the drain valve seals are not rubber-based, but are made of something like Delrin or Teflon, I wouldn't use the product.

On the other hand, Silicone works and is safe.