Ah, black water. In the context of RVing, the muddy Mississippi is positively sparkling compared to our version of black water. Last year, on our last camping trip, I went to dump said black water and found we had a bit of a problem.
Our black water system has two dump valves. One is on the right side of the RV, right next to the holding tank, and one is one the other side where the dump tube fits for draining into the dump station. I guess there are two so that you have a backup in case one of them fails.
The general dump procedure is to connect the hose, and open the dump valve on that side. Nothing comes out because the other valve is still closed. Then, I go around to the other side and open that valve, unleashing the torrent from Hell. Of course, this means that I'm not able to make sure that the dump tube stays in the hole in the ground so I have to race back around to the other side and hope that the end of the tube isn't whipping around like a garden hose, spewing effluent hither and yon. Don't laugh, it's happened.
I had noticed on a few previous trips that I would get a couple of drips from the valve on the tank side during the course of dumping. It's kind of gross but nothing really bad and frankly, I was kind of hoping it would go away on it's own.
It didn't.
This last time, it was pretty much pouring out of the valve. It happened to be doing this while the campground owner was standing there talking to me about his nice campground. Oops.
Of course, I didn't do anything about it at the end of the year so, with our first trip scheduled for Memorial day a couple of weeks away, I had to fix it.
The first step was to drain the system. I had drained it after the last trip but I had put antifreeze in over the winter so I had to empty that out. I ran the hose into the camper and had Deb put a bit of water in the bowl and flush. I cut off the top of a gallon milk jug and started ferrying buckets of goop from the camper inside to the toilet.
And ferrying.
And ferrying,
And ferrying.
I think I moved about 25 gallons of slurry into the house. Yuck. I called it quits when the water was running somewhat clean.
This weekend, I took a look at the leaky valve. The valve is a knife valve which means that it's basically a gate that you push in to drive a blade across the with of the pipe to cut off the flow. The valve is sandwiched between two flanges and held in place by four bolts in the four corners of the flange. The first thing I noticed was that one of the corners of one of the flanges was completely destroyed. Hmm, I guess that's probably why it's leaking. I got a couple of wrenches to take the bolt out and, as I turned it, the corner just disintegrated and the bolt basically just fell out. Great.
As I looked at the damaged flange, the ramifications began to sink in. If the flange is broken, I can't fasten a new valve between it and the other one since there's nothing to put the bolt into. In order to put a new flange in, I'll have to cut the other one out of course, but it's right next to an elbow so there's not really any room for a coupler that I would have to get to splice in a new flange. As I look at the whole system, I'm coming to the realization that I'm going to have to cut the pipe on the other side of the elbow and re-build the entire elbow and flange assembly. Wonderful.
I go ahead and attempt to undo the other three bolts holding the valve in-place and proceed to twist the heads off of each one. I guess there's a bit of rust going on down here. I finally got the bolts and the valve out. Mercifully, no liquid came out but the smell was less than pleasant.
I also noticed that the other flange, the one that goes into the black water tank is also damaged on the same corner as the destroyed one. The hole in the corner looks like a "C". It might be able to hold a bolt but it could be dicey.
I got on the web to see if there was any info on replacing black water valves. There were a few posts but nobody had any info on what to do when you had to splice in new flanges. I found one post where a guy suggested using MarineTex or equivalent to repair broken plastic parts. I remember Dad telling me about MarineTex and how it was a wonder material - a plastic that hardens into a sand-able, drill-able material that fixes anything. If figured that might be a good thing to use to reinforce the "C" on the tank flange.
This weekend I went to Home Depot to get the new elbow, couplers, and new pipe. Luckily, they had 2 foot lengths of pipe so I didn't have to buy 10 feet of it. Of course, I forgot the MarineTex so I had to go back and get that. I didn't find MarineTex exactly but I found a similar material that they said would do the same thing. Basically, it's like a putty that comes in a "log". You cut off a section and knead it in your fingers which mixes and activates the two components of the epoxy. You press it into place and wait an hour for it to harden.
To fix the "C" I decided to just mash a bunch into the hole and form a new corner. Then I could drill a new hole and have a stronger corner. As I was thinking about how that would work, I realized that I could probably just rebuild the destroyed corner of the other flange in the same way and not have to remake the entire flange/elbow configuration. So, I proceeded to rebuild the damaged corners, applying a layer of putty and letting it cure for an hour, and then repeating the process a couple more times to build up the missing corner.
After building up what I figured would be enough of a corner, I went about getting the holes drilled and the valve installed. The hole with the little damage was easy. I put the valve in place with two bolts in opposite corners and ran a drill through the hole in the valve that was over the repaired hole. The drill zipped through and, when I unbolted the valve, I had nice clean, repaired corner.
I bolted the valve into the other flange and drilled through into my totally rebuilt corner in the same way. I ran the bolt through and found I didn't have enough bolt to get the nut started since I had built up so much putty. I had planned on that though so I got out the trusty Dremel and ground down the hardened putty/corner enough so that I could get the nut on the bolt coming through. I fastened everything together and gave it a quick leak test.
So far, so good. I cracked the rebuilt corner a bit when I was tightening the bolt so I added more putty in the cracks and tried to beef it up a bit more. I'll be able to give it a real test this weekend when we hit the road.
Let's hope she holds.
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