Changing a waste valve

[Riverdog]

I have to replace an in-line black water waste valve.  I did a search of the forum & library to see if there was a procedure outlined but didn't find any.  Does anyone know of any handy do-it-yourself RV repair links where I could look?

 

[Weewun]

Not much to replacing the Valve. 

1. Make sure you have a new valve (available at any RV store).

2. Drain both tanks, be sure to flush the Black Tank thoroughly, it will make for a cleaner job.

3. Remove the four bolts/nuts holding the old valve to be replaced.

4. Remove the old valve.

5. Clean the mounting surfaces thoroughly.

6. Lubricate the mounting surfaces with Vaseline or Gly(a clear grease available at Marine Stores).

7. Install the new Valve in place and re-insert the bolts and nuts after lubricating them.

8. Tighten the nuts equally so as not to warp the Valve seating.

9. Put water in the Black Tank and checks for leaks.

10. No leaks, wash your hands and have a cool-one.   

 

[Riverdog]

Thanks - sound pretty straight forward.  I assumed they were glued on like PVC often is, however bolted on makes more sense as valve do go bad an will occasionally need to be replaced.

 

[Ned]

I would suggest replacing the steel bolts and nuts with stainless hardware.  The furnished ones will rust over time and can be a problem to remove in the future.

 

[Tom]

I did a search of the forum & library to see if there was a procedure outlined but didn't find any.

Definitely an omission on my part. I'll get something in there.

 

[Riverdog]

Thanks Ned - good idea I'll make sure I get stainless.

Tom - no problem - it looks like this is one of the easy ones!

 

[bross]

I had to change the gray water valve on my Montana and changing the valve was the easy part. The hard part was getting to the valve. The Montana has an enclosed underbelly that has to be removed to get access to the the valve. That underbelly is installed with about fifty self tapping screws that have to be removed while laying on your back under the trailer. To top that off, my valve had broken in the closed position and the tank was full. Needless to say, when I removed the valve, while laying on my back under the trailer, I got a face full of gray water. I'd rather have a root canal than do that job again. Good luck.  ;D

 

[Riverdog]

Bross - fortunately it was the gray tank for you.  Mine is the black tank but I made sure I rinsed it out very well - so hopefully I don't get any surprises when I fix mine.

 

[Weewun]

Riverdog, when I said tighten the nuts/bolts 'equally' I really meant 'evenly'.  A Torque Wrench is not necessary but it is important that you pull the pieces back together 'evenly' to prevent warping.

 

[Riverdog]

I understood - thanks.  Kind of like tightening a tire, cross back & forth & gradual to get even pressure & a good seal.

 

[donkita]

So, any advice for changing a black water valve that is stuck closed, and the tank is full. Duck and cover?

 

[Tom]

When someone asked me that question, I suggested they drive to a dump station that has plenty of concrete around it and a water spigot. Wear some gloves and rubber boots, maybe even wear goggles or a mask. Undo the 4 nuts, remove the bolts, and slide the valve out. Be prepared to clean up the mess when you're done.

Good luck. Be sure to have someone take a video and post it here for the benefit of others  ;D

 

[donkita]

Thanks (sort of). I figured that's about where I stood. I may let the repair shop handle this one. Some things money can buy

 

[Marc L]

Maybe call a septic company, they may have a hose with the truck that will fit in the toilet and you can clean most of it that way before doing the repair.  Also, when replacing it, jack up the side of the trailer where the valve is as much as possible, that will keep some of it in.

Or call Mike Rowe and you may be featured on Dirty Jobs.

 

[donkita]

You're all hilarious, but I do appreciate the advice and suggestions. I still think I'm going to turn this over to a professional. Luckily, I had dumped the tank, but then I filled it up from the holding tank to flush it out; then the valve/gate failed to open the second time. So the water may not be too bad.

 

[Frizlefrak]

I actually had a black tank valve go bad....as in stuck shut, with the tank about 3/4 full once.  I pulled the handle to drain it, and the handle came off in my hand with the blade firmly stuck in the shut position.

We were camped out on some land we have, so fortunately had a bit of latitude if worse came to worst.....I could park it over the septic tank opening, puncture it with something, and move quickly out of the way and pray the mess was minimal....but on the drive into to town to get the new valve, my wife came up with a brilliant idea.

The land is on a gentle slope, but there are some hills and berms here and there....she suggested I hook it up to the truck and tow it onto an area that has a decent incline, with the trailer leaning to the right.....which put the valve on the high side. I got it onto a fairly decent tilt...nowhere near in danger of tipping over, but leaning pretty good to the right.  I crossed my fingers and loosened the valve.

It didn't smell very good, but nothing escaped.  Took about 3 minutes to change the valve.  I pulled the trailer back over to the septic tank, hooked up the slinky, pulled the new valve and let it rip. 

Necessity....the mother of invention. 

 

[Ned]

The plastic handle on our black water tank broke but there was enough shaft left to get a vice grip pliers on to open and close it.  When replacing the valve, be sure to get the metal handle model and not the plastic one.

 

[donkita]

Good to hear from some voices of experience. The slope idea sounds promising. As I said, though, I had dumped the tank and then filled it pretty full in prep for a good flush, and then the valve wouldn't open again. The problem is that the handle/cable/rod/etc. still pull out fine, but the final rod is apparently no longer attached to the valve gate.The guy at the RV place said it had probably come unscrewed from the gate, and I should be able to screw it back in. Haven't tried yet, but the problem I anticipate is that when the handle/etc is pushed all the way in, so is that rod, and I can't get to it to turn/screw it back in. If the rod is detachable from the rest of the assembly, I might be able to try it that way. Or, if I could get the rod to pull all the way out, I may be able to get something else into the screw hole in the gate (assuming that IS the way it was connected), and pull it open manually. To do this, I suppose I would have to cut or break apart the back part of the valve assembly.

 

[mayfair]

The plastic handle on our black water tank broke but there was enough shaft left to get a vice grip pliers on to open and close it.  When replacing the valve, be sure to get the metal handle model and not the plastic one.

EXCELLENT tip !!

I just replaced a plastic one on mine because it was broken. That metal one is night and day better than the plastic. It's bigger, and fits your hand better. I plan on replacing the other one now. They're awesome !!

 

[mayfair]

The guy at the RV place said it had probably come unscrewed from the gate, and I should be able to screw it back in.

That's a pretty good question.

I wonder if when the valve fails happens, if you could srew something else ( larger ) in and open the valve. Like, screw in a lag bold or something, open the valve, and then change the valve assembly to a new one once you've drained the tank.

I wonder if that would work?

Has anyone tried that?