Well, it was time. I've noticed a couple times that when I removed my sewer cap, some liquid would sometimes come out. Not much, but there shouldn't be any. One or both of my dump valves was bad.
The valves are available at RV parts stores for $10 - $12 each. You need one 3" valve and one 1 1/2" valve. This isn't a job you want to do multiple times so you might as well replace both at the same time. The valves come with new gaskets, bolts, and nuts.
Overall the job is actually quite easy; it's the contents of the valves that makes it problematic, not the mechanics of it. I don't have any pictures because I didn't want to contaminate my camera, but it's a straightforward job. Ready? Here we go:
- Find out how much the RV shop will charge to do it. It may be worth it to pay for it to be done. As I said above, it's not a difficult job but it does rank up there in the "List of Nasty Jobs to do in a Camper". I would rank it first on that list, actually.
- Assuming you still wish to do the job yourself, first, dump the tanks well. As well as you possibly can. Flush 'em with water and re-dump. Repeat a couple times. Think about what goes in them and what you want to see when you pop off that blackwater valve!
- I had the camper parked so that the front of the camper was facing down a slope. In hindsight, a better solution would have been to have it set up so that the left side of the camper is higher than the right, so liquid in the tanks would flow away from the valves. The higher the better.
- Assemble your tools. You will need:
- Wrenches and sockets - mine were 5/16", 3/8", and 7/16". Note you have to hold the bolt and turn the nut, so you'll actually need two tools for a single bolt.
- Vice grips - I used needle nose vice grips but regular ones will probably work.
- Liquid Wrench or WD-40 or something like that.
- Plastic to put down to keep your work area from turning into the newest Superfund site.
- A bucket. And an environmentally responsible place to dump said bucket. I used a toilet in the house. Of course there's no reason you couldn't dump the bucket down the toilet in the camper after everything is finished and tested.
- An hour and a half or so - I did it in less but you do not want to rush it.
- Still have your nerve? Good! Spray the bolts and nuts with the Liquid Wrench/WD-40. This won't actually help release them but it will help get the bolts/nuts out of your sockets when they break.
- Spread the plastic on the ground around the drain valves.
- Loosen the bolts and nuts on either side of the dump valves. All 8 of mine broke. Some more than once. You'll need the vice grips for two things: holding on to the bolts that you can't get a wrench on because of the rust, and for getting the broken pieces out of your sockets. Good thing new hardware is included in the package.
- As you loosen the bolts and nuts, you'll get some dripping. Once you loosen the last one, you'll get a serious drain flow if there's anything left in the tanks. This is why you need the bucket. I had about a third of a gallon of graywater in my tank and perhaps half a gallon of blackwater. Try to avoid dropping the bolts/nuts in the bucket - you do not want to go on any unsavory fishing expeditions.
- I removed the bolts and valve for the graywater tank, then once that was finished draining, I emptied the bucket, then moved to the blackwater tank. The order isn't critical.
- Once it's all apart, set the old valves aside and make sure the original gaskets are with them (not still stuck on the pipes). There's a gasket on each side.
- There are a couple ways to reassemble it, but I placed the blackwater valve on the T-pipe and put new bolts through two of the holes to help hold it together (no nuts, just the bolts). Then I put the graywater valve on the pipe from the tank and slipped a bolt through a hole there, again, to help hold it once I got it in place.
- Being careful not to drop any of the gaskets into the bucket, I put it together. It's complicated because the two valves are at 90 degree angles to each other, so you have to kind of fight against one to line up the other one. While you're doing this, be careful that the gaskets are not getting misaligned.
- Once it seems to be fitting together well, put bolts and nuts in all eight holes and finger-tighten them. I'm usually good for dropping at least one or two bolts for each hour of a given project, but this time I didn't drop a single thing. It amazes me how my coordination was improved by having a bucket of you-know-what sitting there.
- I tightened them sequentially - a few turns on one, then to the next one, and so on, around and around, so that the pieces would be pulled together more evenly. I don't know if this is necessary but I wasn't really eager to break something or have a gasket pop out of place.
- After the bolts are good and tight, run some water into each tank and check for leaks.
- If there are no leaks, go ahead and clean up the mess. If there are leaks, loosen the bolts, and check the gaskets - it's likely one got messed up while you were pushing them back into place.
- Have a beer/cola/coffee/Margarita/drink of your choice - you've earned it!