There’s a parallel to the old “You don’t miss your water until your well runs dry” tune. It’s called, “You’ve got no place to go if your holding tank valves won’t open.”
A sticky holding tank valve is a pain in the neck. A stuck (or broken) holding tank valve is a really big issue if it happens, but can easily be prevented. An understanding of how dump valves work helps us take better care of them. All that “goop” in your black water and gray water waste tanks is held in place by the tanks’ dump valves. A little plastic gate rides between two rubber seals (one on the outside of the gate and one on the inside), preventing the stuff from rolling out. The gate is pulled aside, or open, by an attached stainless steel rod. A small T-shaped handle allows you to grab the rod and pull back the gate, permitting the contents to flush forth.
It’s a simple concept, but a couple of things can get in the way of a simple operation. If the rod gets stuck, or the handle breaks, you have a decidedly difficult issue. Maintenance is easy and inexpensive. First, keep the rod well lubricated. When you dump a tank and the handle is pulled to the open position, simply shoot the stainless rod with a good shot of lubricant spray containing silicon or Teflon. Now “work” the valve open and closed a few times.
DO NOT USE the old standby, WD-40. WD can work its way into the seal at the end of the rod shaft and gum it up, making it extremely sticky.
There are other methods of lubricating things. Some manufacturers brag about lubricants that are added to their holding tank treatments. Do they actually work? They may help keep the gate itself lubricated between the rubber seals. However, there is a nice seal that prevents holding tank contents from actually getting onto the rod. How’s the lubrication to work there? We scratch our heads on that theory.
Some RVers who have been flummoxed by sticky valve handles have gone a step further than the simple advice to lube it every now and then. By adding a Zerk fitting (grease fitting) to the dump valve assembly, they pump grease into the cavity around the steel rod. We’ve never tried it, and do have a couple of concerns. Is it possible that the application of petroleum-containing grease might cause the rubber seal to deteriorate—eventually leading to a mechanical breakdown or possible leakage of holding tank contents?
But for those who would like to know more, here’s how the job has been explained to us: With the valve closed, in the area immediately adjacent to where the stainless-steel actuating rod comes out of the holding tank valve, bore a 3/16-inch hole through the plastic and into the cavity. Then use a 1/4-inch x 28 thread tap to tap threads into this hole. Screw in a 1/4-inch Zerk fitting until the shoulder of the fitting is snug to the valve body—don’t over-tighten. Pump the cavity full of grease and the theory says you’ll keep the actuating rod freely operational. As we’ve said, we’re not recommending this procedure, only commenting on it.
Regardless of your choice of lubrication approaches, you need to keep an eye on the valve handle. If that T character breaks, opening the valve is tough. Replace it if it cracks, or if any part of it breaks off. Again, it’s an easy fix, if done properly. With the valve open and actuating rod exposed, wrap a rag around the rod, and grasp the rod firmly through the rag with a pair of pliers. Now turn the handle counter-clockwise by hand to remove it, and screw a new one on firmly. Be careful not to ding or in any way damage that steel rod, as a rough rod can create problems—like tearing up the shaft seal.
Smooth dumping to you!
Russ and Tiña De Maris are authors of RV Boondocking Basics, a how-to guide for RVing “off the grid.” Visit www.icanrv.com for more information.
I have put vegetables oil in gray tank. It works for a while, then I put more in. I do lube the pull handles. Wish I could find something that is good durning cold weather. I full time and in the winter at times.
Hi Gary,
Thanks for your interest. To answer your question, some RVers swear by the addition of various kinds of oils to their holding tanks, via the drain. But unless the choice of “lubricants” is one that will go into suspension with water, the lube will simply float on the top of the tank water and hang out there until you finally dump the tank. It seems that a shot of lube directly to the valve rod is about the only practical solution, at least from our experience.
Hope this helps.
Russ
tried 2# new 3 #blk valves last mo, both are sticking (hear rubber dragging on pull leaver shaft.
tried veg oil, also gallon dish soap,and sil grease fitting , all did not help .
called Ven val 4,5 times no responce waiting for Her to respond.I wonder if she overworked wlth
my type of pr0blem. ???
U got silicone greases too. Coconut oil, jojoba oil, grapeseed oil, olive oil will all help.
Long time ago a tech told me to use water pump lubricant in the waster water tanks to keep seals pliable and free.
If you are going to use grease a on this valve I suggest a food safe grease. A plumber friend of mine told me to use it on my clean outs when I plumbed my house. It doesn’t harm O rings so it should be fine for these valves.
tried 2# new 3 #blk valves last mo, both are sticking (hear rubber dragging on pull leaver shaft.
tried veg oil, also gallon dish soap,and sil grease fitting , all did not help .
called Ven val 4,5 times no responce waiting for Her to respond.I wonder if she overworked wlth
my type of pr0blem. ???
I have keep my valve at the 5:00 o’clock position but first spray with silicone been that way since 2013 now 2021.
Only lubricated 2 times but started sticking after all these year’s.
went to drain black water tank and handle came out with the cable nothing drained so i pushed cable back so did the end of the cable come off, the gate ? and how do i hook it back up to work
My rod is getting really hard to pull out or to seat the valve fully closed. I lubed once with a “dry” version of WD-40 which contains Teflon™-style Fluoropolymers. I wonder if I should continue using it? I did not use much and I only worked the rod a little, being unsure if I was performing a useful process. I think will go out right now and spray and work the hell out of it and see if it loosens up. I will report back the results.