How Would I Remove A Holding Tank

BobsYourUncle has a great tutorial.

Just a little to add: Both the toilet drain and vent may be glued in. If the toilet line goes through the basement, you can cut it there; same for vent. I used rubber no-hub fittings to reattach both.

Regards,
Doug

I would say that you should first determine if you have a leak when you are moving only, or does it leak when you are at rest too?

Obviously the way to do this is to clean it out first, but after that remove access panels and pack paper towels around all places you think might cause the leak and fill it up.

After a few minutes, start pulling the towels carefully, looking for a telltale wet spot.

If you can't see it, take your small digital camera on close up, and reach up inside and take pictures of the spot so you can determine better your next approach.

I had a leak on my drain line years back and removed the fitting, then dried out the tank by wicking the water out with the rig on a slant. I then tipped it the other way and warmed the area so that I could not detect any wetness on the fitting. I reassembled it with epoxy in the threads and the cracked fitting and it never leaked again.

good luck

BobsYourUncle wrote:
I have pulled a few of them in my days fixing RV's. Not that big a deal to do really.

I know they vary a bit from unit to unit but most of them are held in in a similar fashion.

First thing you have to do is the obvious, Drain the thing!! Then I would do a thorough job of flushing it, even to the point of putting about 5 gallons of water in there and some strong soap and going for a 20 mile drive to slosh the cleaning solution around in there. Not too much soap or you'll have suds blowing out your vent stack! Picture that one going down the road! :B Then rinse a couple times.

You will have to remove your toilet off the floor. Easy enough, undo a couple nuts and lift it off.

Next the toilet flange, which is very likely threaded into the black tank. There will be about 4 screws holding the flange to the floor. Remove those and then twist the flange in a counter-clockwise direction to thread it out of the tank. You may have to use a blunt drift punch to get it started and tap tap tap, not too hard but firmly to rotate the flange.

Now you have to go after the vent stack. Find where it goes through a closet or something. Make sure you have the right one! I have seen these both threaded and glued into the tank. Yours could be either way. Grab the vent pipe somewhere where you can grab it firmly and try to rotate it counter clockwise. Even put a tool on there like a pipe wrench to help grab it to get some leverage. But CAUTION here. It might be glued in. If so and you crank too hard you can break it. Don't reef on it too hard! And don't distort it with a pipe wrench!
If it doesn't give then you have to cut it off. You want to cut it as close to the floor as possible, BUT! You have to make sure you do this in an area where you can get in there and glue to pipe back together, using an ABS coupler for the task. You gotta be able to get at it to mend the pipe so use diligence here. When you cut it try to cut it nice and straight to make the fix it job easier. And leave enough sticking out of the floor to attach a coupler.

You may have to remove the top of your vent on the roof to give the pipe some wiggle room. Also you may need to restrain the pipe from falling when you drop the tank. Duct tape and some light rope tied up to something will work here.

OK, toilet and vent pipe taken care of.

Now your sewer pipe. Simple job here - Cut it close to the tank, but make sure you leave enough to comfortably rejoin the pipe with an ABS coupler. I use a recip saw with a fine tooth blade.

Crawl under the thing and you should be able to see the wires for the sensors attached to little studs on the side of the tank. Remove the nuts, put the wires aside, making sure you record which one goes where. I like to take a picture of things like this, print it and write on it anything I need to remember. Sensors never work right anyways but thats another tutorial! :B

The flushout should be easy enough - Remove the white hose - it is likely clamped on. And the flushout itself? I have never removed one so can't offer on how it is attached. Should be self explanatory, perhaps a pipe to cut and splice back on after. Just remember that anything you cut should be done as close to the tank as practical, but leaving a comfortable working piece to repair it after.

Now you are ready to drop the tank. I use a floor jack and a wide piece of wood such as about a 20" piece of 2X12 or 2X10 or a 2 foot square piece of 3/4" plywood or similar.

Place the floor jack under and jack it up until the tank is fully supported. If your axles are flipped you will have lots of room to do this. If not, you should still be ok, but may want to drop your landing gear way down... I guess that would be way up to lower the hitch. You know what I mean anyhow, drop the front of the trailer. I'm assuming the black tank is behind the axles.

Then remove the bolts that go up into the retaining brackets into the floor joists. Some tanks have brackets, some tanks have belly straps. Anyways, remove them and set aside.

Now release the pressure on your floor jack and s l o w l y let it come down, all the while looking for anything hanging up anywhere around the tank, or some mystery thing that we forget to detach!..... As the tank drops down you should be able to peek up over the top to make sure all is clear. A small mirror and a flashlight helps here.

Caution on some wayward "stuff" on top of the tank from the leak.
One of the leakers I fixed was the toilet flange itself had a big nasty crack in it. Soup on top of the tank - yuk!

Let us know how you make out! :)

very good tutorial,,, thank you
I was unaware that the flange threaded into the tank, thought it was probably glued

my old trailer I thought about exploring the possibility of a larger black tank, as it seems to always fill up in 5 to 6 days, would like to stretch it out for 8 or 9
my new one I may some day open the belly pan to explore that possibility, if its possible, it may be worth the effort for the extra usage and convenience if a CG washroom is not close by

Quick answer is "Very Carefully" :b:B

But, I have to say that I agree with Path1.....do a bit more research on what is leaking first.
You may be able to remove the toilet, so as not to cut the drain line....and all you may really have to do, is lower the tank, not completely remove it, so the electric sensors may have enough slack in them, to stay connected.
If not, remember to number each wire on both sides of the cuts.

Good luck.....and if you decide to do it, take pictures of the process....might as well enlighten the rest of us:)

Good Luck:)

I have pulled a few of them in my days fixing RV's. Not that big a deal to do really.

I know they vary a bit from unit to unit but most of them are held in in a similar fashion.

First thing you have to do is the obvious, Drain the thing!! Then I would do a thorough job of flushing it, even to the point of putting about 5 gallons of water in there and some strong soap and going for a 20 mile drive to slosh the cleaning solution around in there. Not too much soap or you'll have suds blowing out your vent stack! Picture that one going down the road! :B Then rinse a couple times.

You will have to remove your toilet off the floor. Easy enough, undo a couple nuts and lift it off.

Next the toilet flange, which is very likely threaded into the black tank. There will be about 4 screws holding the flange to the floor. Remove those and then twist the flange in a counter-clockwise direction to thread it out of the tank. You may have to use a blunt drift punch to get it started and tap tap tap, not too hard but firmly to rotate the flange.

Now you have to go after the vent stack. Find where it goes through a closet or something. Make sure you have the right one! I have seen these both threaded and glued into the tank. Yours could be either way. Grab the vent pipe somewhere where you can grab it firmly and try to rotate it counter clockwise. Even put a tool on there like a pipe wrench to help grab it to get some leverage. But CAUTION here. It might be glued in. If so and you crank too hard you can break it. Don't reef on it too hard! And don't distort it with a pipe wrench!
If it doesn't give then you have to cut it off. You want to cut it as close to the floor as possible, BUT! You have to make sure you do this in an area where you can get in there and glue to pipe back together, using an ABS coupler for the task. You gotta be able to get at it to mend the pipe so use diligence here. When you cut it try to cut it nice and straight to make the fix it job easier. And leave enough sticking out of the floor to attach a coupler.

You may have to remove the top of your vent on the roof to give the pipe some wiggle room. Also you may need to restrain the pipe from falling when you drop the tank. Duct tape and some light rope tied up to something will work here.

OK, toilet and vent pipe taken care of.

Now your sewer pipe. Simple job here - Cut it close to the tank, but make sure you leave enough to comfortably rejoin the pipe with an ABS coupler. I use a recip saw with a fine tooth blade.

Crawl under the thing and you should be able to see the wires for the sensors attached to little studs on the side of the tank. Remove the nuts, put the wires aside, making sure you record which one goes where. I like to take a picture of things like this, print it and write on it anything I need to remember. Sensors never work right anyways but thats another tutorial! :B

The flushout should be easy enough - Remove the white hose - it is likely clamped on. And the flushout itself? I have never removed one so can't offer on how it is attached. Should be self explanatory, perhaps a pipe to cut and splice back on after. Just remember that anything you cut should be done as close to the tank as practical, but leaving a comfortable working piece to repair it after.

Now you are ready to drop the tank. I use a floor jack and a wide piece of wood such as about a 20" piece of 2X12 or 2X10 or a 2 foot square piece of 3/4" plywood or similar.

Place the floor jack under and jack it up until the tank is fully supported. If your axles are flipped you will have lots of room to do this. If not, you should still be ok, but may want to drop your landing gear way down... I guess that would be way up to lower the hitch. You know what I mean anyhow, drop the front of the trailer. I'm assuming the black tank is behind the axles.

Then remove the bolts that go up into the retaining brackets into the floor joists. Some tanks have brackets, some tanks have belly straps. Anyways, remove them and set aside.

Now release the pressure on your floor jack and s l o w l y let it come down, all the while looking for anything hanging up anywhere around the tank, or some mystery thing that we forget to detach!..... As the tank drops down you should be able to peek up over the top to make sure all is clear. A small mirror and a flashlight helps here.

Caution on some wayward "stuff" on top of the tank from the leak.
One of the leakers I fixed was the toilet flange itself had a big nasty crack in it. Soup on top of the tank - yuk!

Let us know how you make out! :)

Maybe I'm missing part of story; but I would hold off on removing tank for now. Unless you have a really easy tank to pull.