Gray Tank Valve Not Closing - Need Easy Fix

So I went to dump station after 2 days boondocking, unscrewed garden hose cap before removing 4"  cap.
Gray waste water from shower & bathroom sink drained out, about 1-2 gallons.
Definitely not black waste or from kitchen sink.
Is there some way to fish/snake some type of brush or other tool to clean ....say, hair from shower
or some other object?

Is there a common cause?

Boondocking again in 8 days!

The easiest thing to do is buy a spin on valve and put it on the end of your sewer pipe. Then put the cap on that when done dumping. Many of us do that. It serves as a backup valve in case one of the drain valves are leaking by like yours, and you can transfer water from one tank to another if need be.

https://www.amazon.com/Valterra-T58-Twist-On-Waste-Valve/dp/B000BGHYJS

Is the valve accessible?  If you can get to it, it's not that hard to remove the valve from the plumbing - just four bolts and nuts, then pry the flanges apart and the valve will come out.  Then you can clean it or replace it and reverse the process to re-install.

You asked if there was a common cause. I think we see it more in black water valves because crap gets stuck in the track that the gate slides in and prevents the valve from closing all the way. Not so much in gray tank valves especially the bathroom tank valve but it does happen.  I had a issue with all 3 of my valves. The problem was that they were operated by a steel cable similar to a brake cable on a bike. If anything got into the track, the cable would just flex when shutting the valve and wasn't able to overcome the crap. I ended up by removing the cable assembly and went with a extension shaft on all the valves. No more issues at least not yet. Sometimes you can just fill the tank with fresh water and add some septic tank chemicals like ROEBIC 57 or RIDEX and let it sit for a few days, then dump it.

Like Lou said, these valves are real easy to replace as long as you can get to them and they're not expensive.

Rene,

I?m curious to find out more about your solution. Where do you access the valve at after your mod?  Mine is in the water hookup compartment, and I don?t see any way of replacing the cable with anything solid.

I have an intermittent black tank problem. Sometimes the valve seats fully closed, sometimes it doesn?t. I?ve instaled a spin on valve as a back up like you mentioned, though I?m worried about that if I cap in freezing temps this winter.

I generally use the built in black tank flush when I dump the tank. Sometimes it works to help seat that valve, other times it doesn?t.

Thanks!

dlshunter said:

So I went to dump station after 2 days boondocking, unscrewed garden hose cap before removing 4"  cap.
Gray waste water from shower & bathroom sink drained out, about 1-2 gallons.
Definitely not black waste or from kitchen sink.
Is there some way to fish/snake some type of brush or other tool to clean ....say, hair from shower
or some other object?
Is there a common cause?
Boondocking again in 8 days!

Click to expand...

dlshunter
Are you sure the bathroom sink in your RV drains into the gray tank?
(Many drain into the black),

ip076 said:

Rene,

I?m curious to find out more about your solution. Where do you access the valve at after your mod?  Mine is in the water hookup compartment, and I don?t see any way of replacing the cable with anything solid.

I have an intermittent black tank problem. Sometimes the valve seats fully closed, sometimes it doesn?t. I?ve instaled a spin on valve as a back up like you mentioned, though I?m worried about that if I cap in freezing temps this winter.

Click to expand...

I had to lower the belly. I then removed the cable operated valves and installed the standard valves both facing the RV frame. The one on the drivers side was around 12" from the frame. Doing some close figuring, I was able to drill a 1/4" hole through the frame and installed a extension rod and connected it to the valve. I then made a handle for the end of the rod. I did the same thing on the black tank which was on the passenger side of the RV.

I have a similar problem.  On my FW, I have a valve like this  https://www.rvupgradestore.com/3-WASTE-VALVE-WBAYONET-p/89-8304.htm  installed on my sewer line, with a cap on it.  It stays in place all the time.

When I drain, I attach a short clear extension to the valve, then my sewer line.  When I am ready to dump, open this first valve, then operate the "normal" valves per usual procedure.  Once I am done, I close the sewer line end valve, disconnect the hose and extension, cap the valve and stow the hose.  Done.  No unwanted leakage.

Over time, my valve blockage seems to be clearing.  The valve will remain because it simplifies things and prevents unexpected leaks.

dlshunter said:

So I went to dump station after 2 days boondocking, unscrewed garden hose cap before removing 4"  cap.
Gray waste water from shower & bathroom sink drained out, about 1-2 gallons.

Click to expand...

I'm confused, gardern hose cap for what system? Fresh water, black water tank flush?
Did the gray tank drain?
Based on the way I am reading your situation, it sounds like your gray tank overfilled and backed up into the fresh water fill, thus drained out when you removed the cap. Ddi your gray tank drain when you opened the valve?

Hanr3 said:

I'm confused, gardern hose cap for what system? Fresh water, black water tank flush?
Did the gray tank drain?
Based on the way I am reading your situation, it sounds like your gray tank overfilled and backed up into the fresh water fill, thus drained out when you removed the cap. Ddi your gray tank drain when you opened the valve?

Click to expand...

The OP was talking about one of these:

https://tweetys.com/terminationcap3.aspx?utm_source=google&utm_medium=cpc&adpos=1o5&scid=scplp7797&sc_intid=7797&gclid=EAIaIQobChMI3qv69-uJ3gIVmI3ICh2CeQ8xEAQYBSABEgLQ4_D_BwE

Ok, so the garden hose fitting that I am referring to is just like this...
Valterra T1020-1 Waste Valve Cap - 3" with Capped 3/4" GHT, Black...I like this feature so that I can slightly unscrew and therefore "test" the integrity of the waste system exit before I remove the whole 3" cap, potentially avoiding making a real mess when not expecting it.

So I just ordered the easiest, least expensive fix for this issue,  which many of you suggested!

Twist-on Blade Valve from Amazon...23 bucks.

dlshunter said:

Ok, so the garden hose fitting that I am referring to is just like this...
Valterra T1020-1 Waste Valve Cap - 3" with Capped 3/4" GHT, Black....

Click to expand...

Just like the link (in reply #9) I provided just before you.

I believe you will be happy with that choice!  Note also a well placed screw can make the valve feel permanent, yet still removable needed.