Sunday, October 17, 2021


Is RVer stuck with sticky black water valve?

By Chris Dougherty
Chris Dougherty is a certified RV technician. Here is a letter he received from a reader while he was serving as’s technical editor.

Dear Chris,
Pulling the black water handle on my 2012 Entegra is getting more difficult compared to the gray water side. Is there any way to ease this or prevent it from getting even more difficult? —Ed

Dear Ed,
This is a common issue that black valves have over time and with repeated use. Lubrication wears off and material can get trapped in the track for the knife valve.

The best way to fix this for the long haul is to service the valve. The valve manufacturers like Valterra make seal replacement kits that are inexpensive and pretty easy to change. Once the tank is emptied, rinsed, and has been left open for 24 hours to “dry” out, you can go ahead and begin the job.

All you will need is a wrench, the kit, and a good valve grease. Dow-Corning 111 is recommended. Remove the four bolts from the valve head, and while lightly prying the pipes apart, remove the valve from the two flanges. There will be a rubber seal on each of the flanges. Remove those, taking note of how they seat in the flange.

Thoroughly clean the valve using a brush, cleaner (like Spray Nine) and copious amounts of water. Look for any damage on the valve that might indicate it needs replacement. Once dry, apply the Dow-Corning 111 to the blade of the valve on both sides and operate the valve until it moves smoothly. Install the new seals that come in the kit onto the flange and coat them with the Dow-Corning 111 to help hold the seals onto the flange, then while prying the pipes apart slide in the valve and align the bolt holes and install the new bolts that come with the kit.

While there are other “homebrew” ways of treating sticky valves that may work for a little while, the repair I noted here will make the valve operate like new for a long time.

As a side note, you may not “need” to replace the seals; however, any kink in the seal can result in a leak. For the minimal cost, I think it’s better to go ahead and change the seals. You can also replace the entire valve for a bit more money, but I would still apply the Dow-Corning 111 to the new valve before installing it.

##RVT798 ##RVDT1334


Notify of

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Inline Feedbacks
View all comments
Tommy Molnar
1 year ago

My black valve on our 2012 travel trailer works like warm butter. It’s the grey valve that gives me fits.

1 year ago

Many times, the issue is not so much the valve blade sticking, but it’s the pull/push cable or rod that operates the valve blade that is sticking. Sometimes you can free that up with silicone spray. Eventually the valve blade itself needs service, but many times in between, it’s the cable or rod that needs lubrication.

1 year ago

I think my RV waste pipe system was assembled in place. I had to cut the pipe to remove the valves. Replaced it using a rubber 4″ section designed for the job. If I ever have to do his again, it will be much easier.

4 years ago

Once you have gone through the work of disassembling it to clean it and use the rebuild kit would it not be easier and more practical to just replace the valve?

Harry Salit
4 years ago

In my coach it takes TWO hands to pull the pipes apart , where do I get the third hand to remove the valve?
Even more difficult to replace the valve & pull the pipes apart. Pretty hard for another person to help when you are almost inside the bay blocking their access.
So what is your solution?

4 years ago
Reply to  Harry Salit

Harry, Try cutting two pieces of thin plastic sheet (like the sides of a plastic milk jug). Use these to act as a slide while pushing the valve in place. Once in place, Paul the plastic out and install the bolts.

1 year ago
Reply to  Harry Salit

Is there a way of anchoring and then using a ratchet strap on each of the two pipes. I guess that would mean two ratchet straps.

4 years ago

I’ve never had an issue with a stuck valve but an issue with increased friction in the cable, usually at the handle end. Pull the handle out, spray lots of WD-40 on the exposed cable, run it back in and out several times and it’s good for several months.

Captn John
1 year ago
Reply to  george

WD 40 will gather dust and dirt. A good silicon spray works better.

1 year ago
Reply to  george

WD-40 is not a lubricant.

4 years ago

After you dump the black tank pour a quart of vegetable oil into the toilet. Then operate the valve several times as the oil drains. I have found this works great and it is soooo simple and cheap. The same thing for the gray tank. I put the vegetable oil in my shower drain of an empty gray tank. Operate the valve a couple times as the oil drains.

1 year ago
Reply to  Jim

Vegatable oil works for me, too. In my tanks, it doesn’t even take a cup. Start with an empty tank and pour it in. I usually put it down a sink, so i flush it with some hot water to get it out of the p trap. I give it time to drain down to the valve, then pull them in and out. I was shocked how well this worked, but your mileage may depend on how your tanks drain and your valves are positioned.

1 year ago
Reply to  Jim

Sure can raise heck with the campground’s septic drain field – often at $100, 000 plus. And people wonder why campground costs are rising.

Follow us!