Close coupled grey water pipe repair - MBS2401W

[merganser]

I backed the water tank drain pipe into a snow pile this winter cracking a grey water drain valve flange. The piping is close coupled with the black water tank. The valve gaskets won't let me slip the valve out. I would like to replace the indicated flange but I cannot see how to get it apart without a recip saw. Of course fitting it all back together will be a challenge. Any ideas?

[nomad297]

It looks like you have just enough room to fit a 1-1/2” No Hub coupling to the right side of the valve. Cut the 1-1/2” ABS squarely 3/4” from the reducer coupling, then pull out your valve. When you replace the valve, cut your new piece of pipe about 1/4” short of it touching the existing piece of ABS. Remove the stainless steel band from the No Hub coupling, fold the rubber insert over itself and slip it onto the pipe where the new joint will be. Now, unfold the rubber insert so it couples the two pieces of pipe together. Unscrew the hose clamps on the stainless steel band until they disconnect. Put the stainless steel band over the rubber sleeve and reconnect the hose clamps and tighten them down.

If you understand this and it is something you want to do, let me know and I will go out to my truck and measure the length of a 1-1/2” No Hub coupling so you can make sure you have room for it to fit.

Bruce

[merganser]

Thanks for the response Bruce. There is 1-1/2 inches of pipe between the flange hubs. I looked at the no hubs on line and see most are 3 inches long. I thought they would be too thick to fold back but it is worth cutting one in half and giving it a try.

[nomad297]

Originally Posted by merganser

Thanks for the response Bruce. There is 1-1/2 inches of pipe between the flange hubs. I looked at the no hubs on line and see most are 3 inches long. I thought they would be too thick to fold back but it is worth cutting one in half and giving it a try.

The standard duty 1-1/2” No Hub couplings definitely aren’t 3” long (well, maybe I’m wrong. Ive never measured one before), so after I get into the back of my truck later this morning, I will measure one for you. I will also take a picture and post it here.

Now, if that space you have is 1-1/2” and the Ho Hub coupling is too long, you could just use a 2” Fernco coupling and forego the pipe, clamping the 2” Fernco coupling onto each hub. A 2” Fernco coupling fits a 1-1/2” ABS or PVC hub well enough to make a good seal. And if that doesn’t work, just use a 2”x1-1/2” Fernco coupling, clamp the 1-1/2” end onto the pipe and the 2” end onto the hub. If you clamp it to the hub of the valve, you won’t have to buy any pipe, and there will be room for you to slide it over the pipe and back onto the hub.

Bruce

[merganser]

I like the Fernco 2 x 1 1/2 reducer idea. I had not thought of that one. That would be a quick repair.



I seem to have a lot of time right now so I actually would like to replace the complete line. I think I need the valve flange, eccentric reducer, male/female adapter and a short piece of 1 1/2 inch pipe (which I have). I'm just not sure of how the adapter glues into the grey water tank. I don't know if I can I loosen it with heat and what to use to reinstall?

[DouglasReid]

I see a worm gear clamp on the far right side of the picture. What is that?

Is it something that could be disconnected with that clamp and then just replace the ABS pipe between that clamp and a new male adapter at the valve?

[merganser]

That clamp holds the male/female bushing in the outlet of the tank itself along with some sort of pliable caulking. I am assembling parts to go with nomad297's solution of using a new valve flange with a 2x1 1/2 fernco rubber bushing. That will act as a union to be able to disassemble the string of piping easily when the grey and black water valves have to be replaced. Something FR should have done in the first place.

[cavie]

Go back to the 3" SS clamp and replace everything to the new gate valve. Much easier to do and it will not break the bank.

[Ampdraw]

Can you loosen that tank on the right enough to slide the entire tank back after you remove the 4 blade bolts and open the gap enough to get the new blade in? You only need 1/4” to do it, just don’t break off the plumbing on the top of the tank trying to force the gap open to far.

[merganser]

The tank is held up and in place with J hooks and I don't know how the plumbing is connected to the top of the tank. Dropping the tank may disturb those connections, compounding the problem.

[Ampdraw]

I wouldn’t suggest dropping the tank, yes, there’s plumbing on top of it, but I’ve yet to see an RV where they’ve drilled the holes out to pass unseen plumbing that were drilled with military precision. You only need to move it literally 1/4” to accomplish your mission, I’d bet their hole the plumbing is passing through to get to the tank is at least a 1/4” or more over size and you should be able to get 1/4” of flex from the plastic pipe on top. It sure would make that job a lot easier if you can get lucky like that by just loosening the tank and prying it all over 1/4” to get the blade and gaskets in place.

[Larry-NC]

Originally Posted by merganser

That clamp holds the male/female bushing in the outlet of the tank itself along with some sort of pliable caulking. I am assembling parts to go with nomad297's solution of using a new valve flange with a 2x1 1/2 fernco rubber bushing. That will act as a union to be able to disassemble the string of piping easily when the grey and black water valves have to be replaced. Something FR should have done in the first place.

When replacing split (frozen) gray water piping on mine, I tried to get that eccentric coupling out of the tank. I loosened the screw clamp and still couldn't pull it free. I had more room than you do and settled for cutting the pipe and using an ABS coupling to join to the new pipe.

[merganser]

Finally got the repair finished. Used a 2" Fernco clamped to the O.D. of the hubs on either side. Added a hanger to the system also because the Fernco is not rigid and allowed some movement.

[nomad297]

Originally Posted by merganser

Finally got the repair finished. Used a 2" Fernco clamped to the O.D. of the hubs on either side. Added a hanger to the system also because the Fernco is not rigid and allowed some movement.

You can take care of the rigidity issue and that bulge in the Fernco coupling by installing a 2” stainless steel shear band on the coupling. You’ll be glad you did and it will look much more professional.



Bruce