Removing Black Holding Tank - Need Help!

[wayner1239]

The dump line on my 1992 21' Sovereign drug the ground and cracked the black holding tank. Can anyone tell me how to go about removing the tank for repair or replacement? Also, has anyone had success in repairing an ABS tank? Advice from anyone is appreciated.

Wayne

[wayner1239]

It's slow getting any response to this one. It would be a big help to me to know if the tank is removed from underneath or from inside. From other posts, it seems that most tanks are removed from the bottom but yet some appear to be removed from inside.
I sure would hate to cut the bottom pan out just to find out it comes out from above. Can anyone help?
Wayne

[malconium]

I do not know specifically where your black water tank is in your model AS but I can maybe at least give you a few clues as to what to look for...

First of all you should be able to back track a bit from the dump outlet point to find where your tank is located. If it is mounted below the floor level then it is very likely that it needs to come out from below. If it is located above the floor then there probably is some way to get to it from above. I know my 1973 is likey to be a lot different than your AS but the black tank was above the floor. It was located just below the toilet and its location was somewhat obvious in that the toilete set on a raised platform with the tank under it. From what I have seen black water tanks are almost always as close as possible to the toilet that they service - usually directly under it.

There are repair kits available for ABS tanks (and other types too). I would suggest that you check with an RV supply house. If you do not have one convenient try this on-line one:

https://www.rvpartsoutlet.com/newstore/nojava/index.cfm

The specific page in their catalog that shows a repair kit is:

https://www.rvpartsoutlet.com/newsto...125F1590ABA0F9

I don't know if that has been all that much help but at least it is a start.

Malcolm

[Buttercup]

Not sure if they have repair procedures, but they have been recommended for tank fixes for AS.

www.incaplastics.com

Haven't had experience with this problem yet. I have been doing lot's of research in anticipation. We'll be bringing our new baby home in a couple of weeks, barring any major complications. Please keep us posted on your progress with this problem and fix.

Cheers,
Kimber

[balrgn]

One thing you might want to keep in mind, the piping most likely has a sealant on the PVC where it goes into the tank(s). Mine did, it was like cement, however, when I applied heat to the joints it softened it so that it easily slid out. Check out one of my restoration pages. There a few pics of how it all came apart.

http://www.balrgn.com/Airstream/airs...oject_2004.htm

Sorry it is on a 1975 but may give you an idea. I'm not familiar with later models....
If you do not have a heat gun, the wife's hair drier works, it's just slower going.... GOOD LUCK, keep us posted????

[pjlingl]

Wayner: Those tanks can be welded. The trick is to find an RV repair shop that has a "plastic welder". I do not know specifically about the 22' Soverign, but I have a '93 28' Excella and mine come out from underneath. I had a leak in mine so I cut a portal in the metal cover, patched (or welded) the hole in the black tank, then mounted a cover over the cutout with pop rivits. You probably will be able to get it welded without actually removing the tank. Good Luck

[TomW]

Originally Posted by pjlingl

...The trick is to find an RV repair shop that has a "plastic welder"...

Radiator shops are also a good place to check since so many modern day cars' radiators have a lot of plastic.

Tom

[wayner1239]

Thanks to all of you for the help. When one is as green as I am on this particular matter, every bit of advice is appreciated.
I cut away part of the belly pan to get a better view. I think I will get some repair kits and give that a try before removing the tank. (I know there is a good chance it will not hold - but then again it might.) There is a metal beam about 3/16" thick under one edge of the crack which will make it hard to reach to repair. I am tempted to cut away more of the belly pan to see if the beam can be removed. I doubt seriously the tank can be plastic welded with the beam where it is. It may be a few days before I can work on it but I will post any further developments. Meanwhile, all advice is greatly appreciated.
Wayne

[wayner1239]

I decided to try repairing my tank even though it was cracked all the way across. I used epoxy and sheets of ABS plastic to repair the flat sections. Around the drain, I used ABS cement and fiberglass cloth. I then used a mixture of ABS shavings and Acetone (I put the mixture in a glass bottle and stirred it occasionally for a couple of days.) and covered the repaired area. I also brushed the mixture on the inside of the tank over the crack.
The ABS/Acetone mixture hardened and appears to be very strong. There are no leaks but only time will tell if the repair is permanent.
Thanks to everyone who responded to this post and others who made all the above suggestions.
Oh, by the way, Airstream Tech Service responded to my email and told me that the tank comes out from the bottom and they have new tanks in stock. It is good to know that if the repair fails, I can get a new one.
Wayne

[balrgn]

Good job! Update after a road trip or two!

[Janets Husband]

Originally Posted by wayner1239

I decided to try repairing my tank even though it was cracked all the way across. I used epoxy and sheets of ABS plastic to repair the flat sections. Around the drain, I used ABS cement and fiberglass cloth. I then used a mixture of ABS shavings and Acetone (I put the mixture in a glass bottle and stirred it occasionally for a couple of days.) and covered the repaired area. I also brushed the mixture on the inside of the tank over the crack.
The ABS/Acetone mixture hardened and appears to be very strong. There are no leaks but only time will tell if the repair is permanent.
Thanks to everyone who responded to this post and others who made all the above suggestions.
Oh, by the way, Airstream Tech Service responded to my email and told me that the tank comes out from the bottom and they have new tanks in stock. It is good to know that if the repair fails, I can get a new one.
Wayne

It seems strange that they would put a ABS tank in for black water.
Poly Ethylene is much more forgiveing in the crack department.
I would think long and hard about replaceing it with another ABS tank.
There are a few suppliers who can sell you the exact shape and size you need.