Tech Tips: Avoiding Sticky Valves

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.

Russ and Tiña De Maris