Tank drain valve

[Kevin D Pem]

So, yes! It is the outlet. Your description indicates that the thread has been stripped.

The picture of the bunghole indicates a smaller hole was drilled in the tank in the fitting that was used. (Yes, the universal tanks have bosses welded on so you can best fit).

Now knowing more, this is my suggestion:

Locate a tap & tap drill.
Open the hole with the tap drill (do this by hand. No power tools).
Tap new thread further into the tank..
Use of a pipe with slots on the end will work as a tap.
Put a bunch of Teflon tape on the pipe thread on a plastic pipe nipple, and screw it in.
If you tape right you will be able to use a hot glue gun and glue the nipple to the boss. Then you should be able to use a coupler to reconnect the water line.

Tip:
Make sure you have extra hose so to relieve any pressure on the fitting. Also be sure to tie up to avoid the line snagging in the future.

 

[Steve and Cindy]

The hole seems to have good threads. But they’re fine threads, as opposed to the common course threaded fittings I keep trying. Also, those threads only go in about 1/4”. Then the hole gets much smaller. That inner, smaller hole has a rubber O-ring in it.
I’ve been watching out for other vans like it. I’ll have to just take a peek under one and see what’s supposed to be there. There’s just not too many around here.

 

[Steve and Cindy]

Well I officially give up. LOL. I have been searching for the solution to this issue for a long time. Contacted everyone I could think of. Visited several RV shops. Googled it to death. YouTubed it to death. And nothing. Two days ago I contacted Roadtrek themselves. Can you believe they had no idea? Two different parts guys had no clue about what goes in the drain hole of my tank. They said the fellow at RVlife has extensive knowledge of the older Roadtreks and would definitely be able to help me. But nope. No idea. He even consulted his manager. They sent me pics of what it could be but those solutions would not work. I have also looked underneath 3 other Roadtreks that I have found in my city and none of them have the tank where mine is. Do I have the only 88 Roadtrek with under hanging tanks that was ever made? Sorry for the rant. I’m just so frustrated.

 

[Kevin D Pem]

You are making this too complicated!!!

You have a fill tube.
You have a vent tube.
You have a tube to pump water out.
And you may have/should have a drain valve.

Original is not a thing on an old rig!!!
Plug anything that you don't need, hook up what you do, anyway you can. It is that simple.

 

[Kevin D Pem]

Oh! I had a vintage trailer that I put a hose with a bib fitting onto the drain fitting, to make gravity filling without my attention a reality. You need to make this fun!!! Be creative, enjoy life,,even while you work!

 

[Steve and Cindy]

You are making this too complicated!!!

You have a fill tube.
You have a vent tube.
You have a tube to pump water out.
And you may have/should have a drain valve.

Original is not a thing on an old rig!!!
Plug anything that you don't need, hook up what you do, anyway you can. It is that simple.

Yes I guess I forgot to mention that in my rant. I give up on trying to find this plug and I’m going to try to fit a new tank in it’s place. But the existing tank is an oddly shaped tank that is designed to fit into the cramped space where it is. A plain square or rectangular tank will have to be pretty small to fit there and I’m not putting it inside anywhere. It’s just such a drag to think that all I need is the proper plug for the existing tank which is in perfect condition. Such is life.

 

[Kevin D Pem]

It is a bummer! Can you take it to a place that could weld a new boss on it or plug the hole, so you can save it?