Roadtrek grey dump valve flange replacement

[rtbill]

One of the dump valve flanges on our 2001 200V van's grey water line is cracked. It's been that way for years but now it leaks. I believe the part I need is either a slip hub (female) or spigot flange (male). Questions:

1. What size? I know that no measurement of a pipe matches the nominal diameter.

2. Actually replacing it: It seems very unlikely I can get the gap for the valve right if I try to glue the replacement on. Not to mention aligning the bolt holes. ABS cement sets up too fast. I am thinking of using a flexible pipe coupling instead. Thoughts?

3. Which part: There is not much room to work with. A slip hub would require a short piece of straight pipe glued into it to fit into the flexible coupling. There might not be room for that. So I think I need to use a spigot flange and put the coupling directly onto the male part of the flange.

Thanks.

[hbn7hj]

Gray water plumbing uses the 1 1/2” dump valve. A 1 1/2” rubber coupler is used to get working room. Hope this helps.

[ChicagoTom]

Not understanding. If I’m reading this right, simply replace the valve. It’s 4 screws and the standard size as mentioned

[rtbill]

Originally Posted by ChicagoTom

Not understanding. If I’m reading this right, simply replace the valve. It’s 4 screws and the standard size as mentioned

Ok I'll elaborate. The flange on the pipe leading from the grey tank is cracked. Hence the valve cannot be tightened sufficiently. The flange has to be cut off and replaced. The space available to work in is severely limited.

I started on this repair today.

Roadtrek did not build these vehicles to be maintainable. A half inch there, a half inch there would have made a huge difference. Instead I'm lying under the van fumbling with nearly inaccessible fasteners releasing occasional drips of sewage, biting my tongue rather than swearing like a sailor being mindful of my neighbor's young kids. Even though the tanks are empty and rinsed and I have the van nose up and high on the passenger side the valves still weeped tinted water when I loosened them.

I quit for the day when it started to rain and I could tell I was losing it.

Anyway, the grey flange is cut off. There is not a wide enough gap between the end of the cut grey pipe and the downstream flange to put the flexible coupling on the grey pipe. I could trim the grey pipe, but it will be tricky to cut off just enough. The short length of grey pipe coming from the tank requires a short coupling, so there isn't much room for error.

The conservative option is to entirely unbolt the black valve, which should allow pushing the dump pipe enough to open an adequate gap at the grey flange to install the coupling. I've already loosened the black valve to get some wiggle room at the grey valve (hence the sewage drips).

Thanks hbn7hj for confirming the pipe size.

[hbn7hj]

Memory says you need to remove the rubber connector to the black tank to get the room you need. Home Depot sells a replacement 3” rubber connector if you need it. The old one may be less than flexible and have to be cut off.

[Want a B]

Originally Posted by rtbill

One of the dump valve flanges on our 2001 200V van's grey water line is cracked. It's been that way for years but now it leaks. ...

How about lightly roughing the area around the crack with an abrasive device.

Then using a powered Dremel tool cut the length of the crack into a "V" shape.

Fill the "V" crack and surrounding pipe with liberal amounts of epoxy?

[rtbill]

I forgot to report the conclusion of this project. Here then:

Originally Posted by hbn7hj

Memory says you need to remove the rubber connector to the black tank to get the room you need. Home Depot sells a replacement 3” rubber connector if you need it. The old one may be less than flexible and have to be cut off.

Our van has a solid pipe from the black tank to the valve.

I realized that fully unbolting the black valve would not allow much additional movement of the pipe because of nearby stuff. So I merely loosened all the bolts. This was a relief because it is terribly difficult to install the upper outboard bolt and nut on this valve (I've replaced the black valve once).

I discovered the dump pipe is fastened to the van about halfway between black and grey valves. The hanger and screw was unobvious because of the undercoat we had applied when the van was new. Once I unfastened the hanger I got some more movement of the pipe and clearance at the grey flange.

I still needed to cut an additional 1/4" off the stub from the grey tank in order to fit the flexible coupling.

Once the coupling was on installing the new grey valve and flange was easy. Everything went back together and tightened up easily.

Thanks again hbn7hj.