1969 Globetrotter Black Tank Replacement Project

[dbj216]

Here I go again. I noticed last spring that the dump valve on the son's Globetrotter had a broken flange. I figured I would replace the valve when I got a "round tuit". I got one last week.

While I was removing the dump valve, I noticed the entire bottom of the black tank was broken out! Great! Another Airstream surprise. This black tank don't need no dump valve! It is a never full black tank. Maybe I can gain a patent on it.

The Globetrotter has an above floor black tank, rather small at that. I was grateful to find the tank was removable without having to remove the shower pan. Whew! Hey, my black tank it white! Can't beat that.

This tank is a "fabricated" tank, not a rotomolded tank. My guess it is ABS, which may not be as strong as polyethylene at the same wall thickness. I don't know if it is the original tank, but I kind of doubt it. The dump valve sewer hose connection bayonet fitting was pointing straight down, about 4" below the belly pan. I think the trailer got run over a curb or bump and the rear of the trailer came down hard on the dump valve, pushing it up into the tank, and breaking it.

Here is the tank as it sits on the bench. I see I can buy a new molded tank from Inca Plastics and others. I wonder if Inca doesn't mold them for every other seller. I better get one on order.

David

[dbj216]

I ordered a new above floor corner bath black tank from Vintage Trailer Supply. It took about 4 weeks to get to me. I received it last week. It is a molded tank with a sloping bottom and a flat top; meaning the tank would like to be "hung" instead of resting on the flat subfloor. I was surprised at this. The 69 Globetrotter has a fiberglass console that the toilet bolts to. I'm not comfortable strapping this tank to a rather flimsy fiberglass piece. The broken tank I took out was strapped to the floor.

I am not using any pre-planned spin weld fittings except the 3" male pipe thread drain fitting that came standard with the tank. I will use rubber grommet seals for the toilet flange and vent pipe. This gives me more flexibility in tank location.

I'm stuck on the drain and dump valve plumbing. The whole stack of fittings is 10" long! I'll have a 4" "dongle" hanging down at the rear of the trailer just waiting to get smacked and broken off. (Floor to belly pan is 5") Right now I am unsure what I will do. Actually I think Airstream built the 69 Globetrotter this way. It would be soooo much better it it was a side discharge tank.

David

[dbj216]

Update on the black tank / new toilet project:

I decided to slope the tank toward the drain "spin weld" fitting, duh! And I wanted to support the fiberglass "console" in the bath. It had had several closet flanges mounted to it and was in a "weaken" condition. So I "boxed" in the black tank to proved the drain slope I wanted, and to provide the strength to the fiberglass console. I used the rubber grommets in the top of the tank for the closet flange to tank seal, and vent pipe to tank seal. I've had good luck with these in the past.

It is a bit dicy to get both all the dimensions to relate to each other when installing a new tank and new toilet. I had to maintain a 1 3/4 distance from the bottom of the toilet to the bottom of the rubber grommet through the fiberglass, wood stiffener, grommet and tank wall. I also had to position the toilet accurately on the console. Once you drill the tank, there is no "rework" options easily available.

I replumbed fresh water to the toilet, and tested for leaks with compressed air. All was good so far. I installed a new Valterra dump valve below the tank and I am now in the process of re-plumbing the gray water lines.

The above floor black tank, and the small rear corner bath was not Airstream's best layouts in my view. Having a side bath with a full bed side to side in the rear would be better, kinda like the new Sports have. And a bottom discharge black tank is a bad idea. It is vulnerable to damage by "tail dragging" up or down a steep incline. That's why ours broke in the first place.

David

[groovzilla]

I'll be plumbing my black water tank soon - great info!

[dbj216]

Thanks groovzilla, I'm glad my little project report is helpful to you. AirForums is where we learn from other's projects.

David

[bambibooth]

That's quite the tank! How many gallons is that one?

[dbj216]

Hi bambibooth: Not enough gallons to do anyone any good. The tank is 7" high, 14" wide, and 34" long with one corner rounded off. I convert this to about 12 gallons, or about a couple dozen flushes.

There is no grey water tank in this 69 Globetrotter. The gray water is plumbed to the 3" discharge port below the dump valve. It's okay if you want to water your own bushes with grey water, but not acceptable in any campground. You gotta connect a sewer hose to the sewer connection to wash dishes.

I could have purchased and mounted under floor waste water tanks like I did my Trade Wind. But that involves a lot of work and cost. We're not ready to do that yet to this trailer.

Oh by the way, the fiberglass console is 9" high, and the new low profile toilet is 14" high. This is a john where you can dangle your feet like a 3 year old.

David

[dbj216]

Today I applied water pressure at the new city inlet connection. I put about 5 gallons of fresh water in the black tank. No drips yet from the toilet flange, grommet, drain port pipe thread, ABS "hubs" to the new Valterra dump valve, and new ABS gray water drain line.

I like it when there are no gushers when you first pressurize the system and test the drain lines.

I did have one small leak at the new Thetford toilet where the "sprayer" hose connects to the flush water valve. I'll blame that one on Thetford. I think easily fixed with another hose clamp. But with my luck, it is probably a cracked hose barb from the factory.

David

[goransons]

Looks great! Black tank installation is my next project on the tradewind too!

[dbj216]

Thank you. I try, and at least make it functional if not pretty. I don't have half the skills you have.

Well, I've completed 48 hours with 5 gallons of fresh water in the new black tank held with the dump valve and no drips. Ready for the "field test".

I guess goofy designs is some of the fun in these vintage Airstreams. My 66 Trade Wind black tank was impossibly bad., see photo below. Maybe it was Airstream's early efforts at a rear bath. This rear discharge tank was about 3" high. Not functional at all. The Airstream owner's manual talks about emptying the tank into a "gopher hole". Poor gopher. I did not replace it.

The bottom discharge above floor 69 Globetrotter black tank is better. I sure don't like the bottom discharge connection required with the rear corner bath. I could have started over with a underfloor tank, side discharge, but wow, what a project that would be. Here is the way the dump valve mounted under the Globetrotter. It hangs even lower due to the grey water pipe connection below the dump valve.

You can see from the photo how pulling over a steeper incline that causes the rear of the trailer to drag will simply wipe off my new dump valve and break the black tank. That's a $300 and many hour mistake. Who ever designed this thing never pulled a trailer. Our Globetrotter does not have "skid rails" welded to the rear of the frame like our other two trailers do.

Other than reattaching the rear corner belly pan piece, this project is DONE!

David

[goransons]

Mine's a bottom discharge too, I'll update my thread later this week. I managed to get the tank mounted and the plywood top tiled, just need to do the toe kick area of the raised tank, and mount the toilet and all the metal trim pieces then I'm under the trailer to work on reverse engineering all the drain line locations since they were all long gone when I got her. Looks like you did an outstanding job getting everything to come together in such a tight place!