Black tank vent snapped off at tank!

[russ240]

After experiencing a mysterious (and odiferous) leak into the sliding door well I went searching and found the black tank vent snapped off at the tank. I can't tell what the original configuration was though. I think the tank had a nipple sticking up and then a collar threaded down over a slip joint ... but I'm not sure. The collar won't budge (may be glued on?) but I can see threads. Can anyone confirm that the tank had threaded nipple sticking up? Better yet, any thoughts on the best fix?

[Tiato]

Wow. Think your original guess is right. I'm surprised that vent pipe was designed / installed in a way that would exert a lot of tension on that joint.

Fix idea. Epoxy a smaller coupling or extension into the broken piece at the tank. Remove damaged piece on lower elbow assembly section pipe or completely double elbow assembly. Use a rubber flex cuff for minimal fix or similar sized corrugated hose hose to replace elbow section to rejoin tank to upper vent pipe.

[InterBlog]

OH MY WORD!!! This kind of failure is STILL happening in the newer Interstate models?? We lost ALL line connections to our gray tank plus the black vent connection, but we thought Airstream had done a re-design to avoid future problems, which were well-known among owners of the older T1N Interstates. I see by your photo that this is not necessarily the case.

I don't believe you can successfully patch it - it won't hold. The same forces that tore it apart to start with will only act again. My husband and I have found that the only solution is a retrofit using flexible couplings (which will bend rather than breaking).

Here is our black tank vent repair sequence... the chosen solution works but is not very elegant because we were burned out from replacing three gray tank connections. The main take-away is that we put a rubber segment into the line (as upside down as it is, but this is for air venting, not liquid flow, so that doesn't matter):

THE INTERSTATE BLOG: FIXING THE BLACK / GRAY VENT LINE ON AN AIRSTREAM INTERSTATE

For further detail on repair strategy, here are our posts on gray tank line repair, including the tank's vent line. The gray tank job was more complicated for a number of reasons that I will let the posts describe:

THE INTERSTATE BLOG: INTERSTATE LEAKING GRAY WATER, PART 1: THE PROBLEM
THE INTERSTATE BLOG: INTERSTATE LEAKING GRAY WATER, PART 2: TANK REMOVAL
THE INTERSTATE BLOG: INTERSTATE LEAKING GRAY WATER, PART 3: TANK RE-INSTALL

Good luck to you. We feel your pain.

[airdreamers]

Does Airstream have recalls? Sounds like poor design on their part. Just sayin". I would make a call.

[Protagonist]

Now you've got me wondering. I encountered an odor on my last trip. I thought it was due to some dog poop I tracked in on a shoe (and which stuck to the carpet in front, ew). The odor from that should have gone away after I cleaned it up, but I still occasionally detect odor. Maybe my black tank vent isn't doing so well, either…

[russ240]

Wow InterBlog, great write up! Looks like I am going to have to brush the dust off my man card and come up with my own solution to this like you did, since I agree going back to the original non-flexible design is only asking for another future failure. I'll post up when I come up with my solution. I'll try to take better pics along the way. I just realized how little you can see in the ones I posted last night.

So seems like the T1N guys are well versed in this issue, but am I really the first NCV3 based Interstate owner to have this problem? I had a problem with the TV's cracking and breaking where they attach to their mounts a couple of years ago that no-one else seem to have encountered as well ... I know everyone likes to complain about road maintenance where ever they live, but perhaps my roads are worse than I think they are? Why am I so lucky to keep breaking stuff? Could it be that Joey Chitwood driving academy I went to?

[russ240]

Protag, just saw your response. I too had some unexplained stink-ies in the cabin off and on for some time before the leak cropped up. And the leak only reared its head when I let the black tank get past 2/3rds full so that it would slosh out through the failure point when driving. The vent pipe cover is two peices and comes off with the dozen or so screws that are obvious. The only hidden gotcha in the disassembly is the headphone jack wire which fortunately does have a plug you can pull once you get the panel off so you can lay it aside ... you just have to be ready to get the tape off of the joint while you are balancing a 5 foot piece of plastic in your hand. Might be good to have a razor knife within reach to cut the tape if you can't unwrap it with one hand. Please let me know if you find you have the same problem!

[dalemonroe]

The tanks I've worked with were made out of ABS plastic like black household drain pipe. ABS glue works well for repairing these tanks because it partially disoves the plastic.

[InterBlog]

Originally Posted by russ240

...I too had some unexplained stink-ies in the cabin off and on for some time before the leak cropped up. ...

Might I recommend the obvious... especially for those of you who are still under warranty:

Put your tablets down, get on your feet, get a magnifying glass if you need one, and check EVERY tank connection that you have in your Interstate, regardless of what year it is.

Look for evidence of the slightest cracks. Our forensics have suggested that these joints don't fail catastrophically - they split gradually over time (possibly leading to a mystery stench well before there is visible evidence of liquid escape). Breakage seems to develop because of normal driving vibrations rather than any unusual event such as rough driving or abnormal impacts such as huge crater-like potholes. And if you don't catch the issue in its incipient stage, the consequences can be serious, obviously. Our black water vent had begun to spew water within inches of our electrical converter.

Oh, and if you have ONE tank line that is split, chances are you might have another. So don't just check the vent.

Particularly if you are under warranty and are having the work done by others, don't allow your service dealer to do some useless goop job (mastic or ABS cement application on a split) and declare it a successful patch. We've seen that kind of work in T1N's that have changed hands, and we suspect that someone may have been trying to pull the wool over the eyes of the previous owners.

You would have to drill down in my blog posts to see this part, but my husband and I believe that this particular tank inlet fixture, which is rubber, has the best promise for a successful retrofit (one pic attached here). If the system can flex at the tank join and then also flex somewhere else in the line itself, a lot of vibration can be successfully dissipated that way.

I could see where repair facilities would NOT wish to do this kind of work (hence the desire to slide by using mastic only). It's labor intensive - either a new tank must be used or the existing tank top must be prepared to accept the inlet fixture. Details in the posts.

If it really is the case that Airstream did not fix this problem properly years ago when it affected so many T1Ns, then I hope that owners really ride them hard about it now, compelling them to finally resolve what I believe is a defective design. People should not have to deal with the likes of this.

[LB_3]

Based on the OP's photos. Airstream is still using the same threaded ABS into polyethylene connections as on our older Interstates.

Before fixing our Interstate leaks as shown in Interblog's links, I called Airstream and asked if they had any old service bulletins with recommended repair methods. Since this was such a common failure on the older Interstates, I was shocked that they claimed to be unaware of the issue.

This is a pic of a failed repair on another T1N:
Friends don't let friends do this to their Interstates.

[tbbrown]

When I Googled Airstream 2007 Interstate, the articles on the waste tank problem popped up. It seems to be a major problem in this RV.
I seems to be worse in the side bath because the tanks are longitudinal, the straps can loosen and the tanks can shift forward when loaded and you have to brake sharply. The plumbing connections have no flexible members so they just shear off at the tank.
The rear bath model does not have the same problem as its combo grey/black tank is mounted crosswise and is better contained by the straps. The articles include pictures of a repair by a DIY owner that includes some flexible joints but it was a major undertaking.
tbbrown

[InterBlog]

Originally Posted by tbbrown

When I Googled Airstream 2007 Interstate, the articles on the waste tank problem popped up. It seems to be a major problem in this RV.
I seems to be worse in the side bath because the tanks are longitudinal, the straps can loosen and the tanks can shift forward when loaded and you have to brake sharply. The plumbing connections have no flexible members so they just shear off at the tank.
The rear bath model does not have the same problem as its combo grey/black tank is mounted crosswise and is better contained by the straps. The articles include pictures of a repair by a DIY owner that includes some flexible joints but it was a major undertaking.
tbbrown

Somewhere deep in the bowels of either Air Forums or Sprinter Forum, there was a post by a rear-bath owner who reported the same issue. I remember this from when I was doing my own research. It might be more common with mid-baths but I don't think it's exclusive to mid-baths.

You said "straps can loosen". In our Interstate, the straps were not of a type or configuration that were 'tighten-able' in the first place. They appear to have always formed a cradle in which the gray tank sat rather loosely. One of the things we did during tank re-install, not explicitly described in my blog posts, was to purchase some adhesive-backed weather stripping material that we used to line the contact surfaces of the straps. Not an ideal solution and I was afraid that the tank might simply continue to slide back and forth and gradually abrade the stuff away, but we figured it would at least provide SOME friction between the tank and the straps for a period of time until we could come up with a better option (plus we had installed the flexible line and joint connections to reduce the chances of damage caused by tank mobility so we were not relying exclusively on the weather stripping). Because there's basically no friction between a polyethylene tank and a thin metal strap.

[73shark]

Another "friction" adding solution would be 3M double-sided foam tape. This stuff is hard to beat when surfaces are properly prepared.

[InterBlog]

Originally Posted by 73shark

Another "friction" adding solution would be 3M double-sided foam tape. This stuff is hard to beat when surfaces are properly prepared.

Yes, some of those exterior-rated tapes are almost frightening in their ability to adhere. I thought about that but then wondered if I might have trouble getting it loose again if I ever needed to later.

I recently got teased by a horse trailer owner because I have not installed a drainage nipple in the bottom of my gray water tank. Apparently this is widely done among horse enthusiasts... some of these trailers are called "slants" (2-horse slant, 3-horse slant, etc.) and they encompass living quarters for both human and equine. Anyway, the word from that faction is, there's no need to accumulate gray water. Just put a nipple in the bottom and allow it to drain out gradually so that there is no discrete pooling or run-off and nobody ever notices. I was a bit surprised at this, but when juxtaposed against the sheer volume of excreta produced by horses, gray water must seem like the ultimate hygiene non-issue.

[Protagonist]

Originally Posted by InterBlog

I was a bit surprised at this, but when juxtaposed against the sheer volume of excreta produced by horses, gray water must seem like the ultimate hygiene non-issue.

I'm surprised they don't install a pump and hose on their gray tank so they can use the soapy gray water to wash out the horse part of the slant! Seems like a perfect way to use the water twice.