Community Forums

roadstar99 · 08-18-2013, 10:11 AM

Our sewer valve won't push all the way in to close off the black water holding tank. The cap prevents leakage while it is on but water from holding tank slowly leaks into the cap. Couldn't find any paperwork to take apart this part of the sewer line to remove and replace valve or see if something stuck in the groove.

Any help would be appreciated.

wjell · 08-18-2013, 10:24 AM

On ours (Older RV) I just fill and flush the toilet 3-4 times before trying to close the valve. I am thinking that will "send downstream" any object that may prevent (or make more difficult) valve closure.

JFXG · 08-18-2013, 10:29 AM

Quote:

Originally Posted by roadstar99

...Our sewer valve won't push all the way in to close off the black water holding tank. The cap prevents leakage while it is on but water from holding tank slowly leaks into the cap.... Any help would be appreciated.

Could be something broken in the valve assembly-- requiring replacement-- but assume first that you've got some paper jammed in the seating groove. I've had this happen a couple of times. Hook up a hose to your black tank flush. Let 5 or 10 gallons build up (approx. 5 gal/min), and then open the valve. Perhaps the rush will clear the piece. Or, while a continuous flow is running down and out the drain, exercise the valve back and forth. This has worked for me. If the valve needs replacement, my sense from visual inspection is that the replacement would not be difficult.

The y-assembly where the black drain and gray drain join can be rotated up and down a bit. If you rotate it upward, this may help to minimize or eliminate any overflow of accumulated leakage when you remove the end cap.

94-Newmar · 08-18-2013, 10:33 AM

As suggested, try to ensure nothing like excessive paper or debris is inside the rubber groove on the gate valve itself. If you're sure it's clear and it's still leaking then just replace the gate valve.. they're easy to do as each half simply unbolts.. if you have good access, 15-20 minute job.

Romeo · 08-18-2013, 10:48 AM

When I had this problem I was surprised how easily the problem was solved by spraying the valve shaft with a silicone spray (or WD40).

You might like to try that first since it is the easiest method.

wjell · 08-19-2013, 07:35 AM

Quote:

Originally Posted by Romeo

When I had this problem I was surprised how easily the problem was solved by spraying the valve shaft with a silicone spray (or WD40).

You might like to try that first since it is the easiest method.

Duh! Why didn't I think of that. I just sprayed mine.

TXiceman · 08-19-2013, 10:36 AM

Quote:

Originally Posted by 94-Newmar

. if you have good access, 15-20 minute job.

That is the key. I had to redo my black water valve and found the gray water had to come out as well to get the needed room to reassemble it. Thais after dropping the under belly to get to the valves.

My advice is to get complete new valves with seals. Some times the seal is not the problem. Outs was leaking back and out the stem as well as not holding the black water. There was a lot of grit and junk left in the tank by the previous owner not using and flushing the tank properly.

In any case, it was closer to a 90 minute job.

Ken

RedWing Nut · 08-19-2013, 11:41 AM

Here is a video showing how to replace a gate valve.

Video

I hold the rubber seals to the new gate valve with plumber's grease when I do it.

roadstar99 · 08-19-2013, 12:34 PM

As usual, I received the help I needed to go ahead with the sewer drain valve repair from all of you. Guess everyone has had this problem sooner or later if they keep their MoHo that long. Thanks to all of you. It isn't as hard as we first thought. Think the thought was worse than the job.
We cleaned both tanks and since we had cleaned the black water tank at our last stop and had chemicals in it, it wasn't that gross to drain. We had a sewer tap placed near our drive so we could use it for the MoHo but there was only about 3 gal of water so we just dumped the bucket of drained water down the sewer. We rinsed it twice till all ran clear. Removed the bolts holding the black water valve in place and it was actually broken. Since we have to replace it, we decided your good advice to go ahead and replace the grey water valve made lots of sense. Really don't want to do this again. We have ordered both valves from Amazon at a good price of $25 including tax and shipping. Should be here and ready to install by Thursday.

Thanks again. I really appreciate the quick responses I always get on this forum.