Holding Tank Replacement

[C&T2]

You guys in the southern states don't know how lucky you are! We are into our 6th month of winter - more snow than usual and weeks of -20c - and I am just dying to get out and start working on our '73 Indian!!!


To that end, I'm trying to get some stuff lined up for when winter finally breaks. The most pressing for me right now are the cracked and leaking holding tanks. The HDPE grey water tank has a good 12"+ crack running from top to bottom on one side, and the fibreglass black water tank is leaking substantially where the drain pipe merges. The two Thetford drain gates are in terrible shape too.


Ideally, I'd really like to replace them both. I had called Mobility Parts about replacements, but they didn't seem to have replacements for a '73... How hard would it be to replace using generic ABS tanks from the likes of Camping World (or any other suggestions?)


Anybody done this before?

[DRMousseau]

My previous Ol' Winnebago Brave, had a single "waste" tank. Being a 40+yr old "northern" RV, the leaky tank was severely cracked and broken with numerous attempts of various unsuccessful repairs.


I believe my ABS replacement was sourced thru Ameri-Kart.com,... they have a broad selection with accurate details of size and dimensions, that were important to me in fitting a near identical replacement in a rather confined space.


Replacement was somewhat extensive. Most difficult was the removal of the old, badly rusted and corroded, carriage bolts that had limited access in attempting to cut some away. Of course it was a thru floor mounting that happened to be directly under the "floor/shower pan" of the tiny bathroom! Since the toilet, flange and fittings also needed replacement, the entire bathroom floor pan and all attached was removed as I opted for an identical solid and secure, thru-floor mounting of the tank. I used heavy stainless carriage bolts and reinforced the tanks mounting flange with aluminum angle stock. Since my tanks were quite exposed and vulnerable to freezing northern temps, I had hopes that any future needed replacements would be much easier should they be necessary.

[Elandan2]

Although the Winnebago site only goes back to 1975, you may find the correct tank for your model by comparing yours to the ones pictured. I noticed you have a D23, a model they still built in '75. The factory tanks are the way to go if possible, they come with any mounting points and the drain fitting attached. When I replaced ours, I found the cost to be comparable to the aftermarket tanks.
I have included the link to the common parts catalogue, the holding tanks are found starting on page E-5.


http://www.winnebagoind.com/service/wincd/1975/75common.pdf

[C&T2]

Yeah, that is what got me a little concerned - when I climbed under I noticed all of the mounting points were very specific (and quite beefy and very rusted). I was looking at Icon Direct and Ameri-Kart replacements, trying to wrap my head around how to affix them...


Thanks for the link - I might call the Winnebago folks again. I think I have the part number off of the grey water tank, but there is nothing like that on the black water. Was fibreglass even used for new units, or is this some sort of replacement tank?



Good Dr, you mention removing the bathroom floor pan - does that mean removing sink/toilet and flooring to get at the bolts?

[DRMousseau]

The "raised edge floor pan", common in the Brave's little "water closet", made the entire containment a "shower"! Not as fancy as my current "apartment", it was kinda nice in that the entire bathroom and fixtures (sink, walls, toilet, etc.), could be cleaned and rinsed down with the shower head.


While the toilet flange is directly above the tank, as in most RVs and Motorhomes,.... the floor drain was thru the floor BESIDE the tank, and directed to a common line from the kitchen and bathroom sinks. This meant that drain trap was ALSO below the floor and exposed to the same elements as the tank. Other drain traps were "protected" inside the RV below sinks, with the bathroom sink (attached to wall only) drain directed thru the nearby wall toward the kitchen cabinet space where it connected to the kitchen drain. A very simple and basic setup that met minimal needs and construction design. Nothing thru or attached to the bathroom floor but toilet and tank mounting bolts, toilet flange, and sink drain.


You'll surely find your system to be jus a tad more, as it entails TWO waste tanks,... and likely a bit larger bathroom/watercloset enclosure! Your sink may actually be on a floor cabinet too. And you may have already determined that the tank mounting bolts do indeed go thru the floor,.... and are likely SOMEWHERE under whatever floor coverings are present! Hopefully, in discrete areas that may non require such extensive floor covering removal! LoL!!! Surrrrrrrrre!

[C&T2]

Called WinnebagoParts and looks like they do have the mould for my grey water tank (takes a couple weeks for production), so that's great! It is the more complex shape... Had a Part number for the black water, but apparently they no longer have the tooling to make them, so that sucks...


Options are to try and somehow fix my fibreglass black water tank (I might just try this anyways) or get a prefab holding tank from one of the afore mentioned vendors. In that case, which is the better material: polyethylene or PVC and why?

[Surfinhurf]

I removed both my cracked and leaking black and grey tanks. They were very odd/specific shapes, Winnebago would not/could not build replacements. I replaced with 1 large aftermarket tank. Not too bad of a job.  I increased my  total holding capacity by 8gal +-.  Before the change over, we rarely filled the black tank, but always had a full grey tank.  Now I can manage grey/black better into 1 tank.  Ill try to get some pics.

[DRMousseau]

Options are to try and somehow fix my fibreglass black water tank (I might just try this anyways) or get a prefab holding tank from one of the afore mentioned vendors. In that case, which is the better material: polyethylene or PVC and why?

For black-water and waste ONLY,... my preference is for ABS. It's more rigid, and a bit stronger than either PVC or polyethylene. It's not as brittle as most fiberglass composites and resists stress cracking better than the other polys. It's greatest weakness is probably heat... it deforms easily under heat extremes. It's greatest advantage, is it's compatibility with ABS flanges, pipe, fittings and WASTE VALVES which are all typical of waste systems are also made of ABS.

[C&T2]

Doh! Yes, I meant ABS, not PVC... I live in Canada, so don't think I'm gonna have to worry about ABS and its reaction to heat quite so much! W%

I think I've found a number of tanks that should fit where my current black water tank is... I believe the mounts are going to be the main issue as I think they are through the floor (my bathroom is bigger, with a separate shower from toilet area)... This is the one thing that will make the wife happy and actually want to go camping, so gotta get it done this spring!

Thanks guys!

[C&T2]

Wow! Time has marched on and I have spent very little time working on our rig - lots going on, but a big part of the time suck was due to getting all new cushions and the original seats re-upholstered (ultimately a terrible experience destined for another conversation, but all-in-all an improvement over the mouse-tunnelled and sun-damaged old ones).


Will hopefully be ordering the replacement grey water tank on Monday, but am planning on trying to fix the fibreglass black water tank myself. The tank itself appears to be fine, the leak is mainly around where the ABS pipe joins with the tank.


So, my question is, how would these two dissimilar plastics normally have been mated in the past? Some sort of rubber gasket, or sealing compound?


While I'm working on these tanks, I'm also going to replace the original Thetford gates with Valterra as they are much easier to fix or replace.

[Elandan2]

As the manufacturer of the Twis-Loc waste valve, I have to disagree with your assessment of the repair of Valterra, and Thetford valves, for that matter. To replace those brands of valve gates and seals, the valve must be split apart by removing the four screws around the waste pipe and then removing the blade assembly. With the Twis-Loc valve, the only screws to remove are just under the handle and then the assembly can be removed with a simple pull on the handle. Have a look on our website, you will find an exploded diagram where you can see the difference. www.dupreeproducts.com It makes the whole procedure much cleaner and all the components are replaceable, or as we recommend, the entire assembly can be replaced, with the result being completely new valve. In addition, the Twis-Loc valve gate and stem are one piece, no more stems pulled out of the valve gate with a full tank. 

[LJ-TJ]

3M has a product for repairing black water tanks with dissimilar plastics. Darned if I can find it now but I believe I posted a like to it a year or so ago. If any of the old timers are still hanging around my be they still have the line. I no for sure it is 3M that has the product. What was it? How to repair polyethylene to polyurethane or something like that. Sorry I couldn't be more specific. Hm?

[CapnDirk]

Many automotive body supply houses carry Lord Fusor products.


https://www.lord.com/products-and-solutions/brands/fusor-repair-adhesives


If it's plastic on a car they have something to glue or bond it.  May want to take a look at their products and procedures.

[DaveVA78Chieftain]

Will hopefully be ordering the replacement grey water tank on Monday, but am planning on trying to fix the fibreglass black water tank myself. The tank itself appears to be fine, the leak is mainly around where the ABS pipe joins with the tank.

The holding tank is most likely polyethylene, not fiberglass.  I have found a rubber flex-joint is the easiest way to join the different types of pipe together.  You find these in the plumbing department at Lowes, Home Depot, etc.



For cracks in the fresh and/or waste tanks, I use the plastic-weld technique using a soldering iron.


EDIT:  Or is that Polypropylene?

[LJ-TJ]

Hey Merlin, We have discussed this in the past and I found a 3M product that glues the two dissimilar plastics together. Anyway to find that post? D:oH!

[DaveVA78Chieftain]

Is this the thread your looking for?
http://www.classicwinnebagos.com/forum/index.php/topic,3611.msg53861.html#msg53861

[DaveVA78Chieftain]

or this thread?
http://www.classicwinnebagos.com/forum/index.php/topic,7640.msg51569.html#msg51569

Anyway, thats all your tank repair threads

[LJ-TJ]

 D:oH! How in the world do you do that. Yes, THANK YOU VERY MUCH. Geeeeezzzzzz  i?? that's the stuff I was trying to tell that young lad about. Wizard. We're going to have to start and call you the Wizard.

[M & J]

We call him Super Dave TJ.

[LJ-TJ]

Ok Super Dave.......the Wizard

[DaveVA78Chieftain]

Actually it is easy
Select Search
Enter search term: tank
Enter Username: LJ-TJ

[LJ-TJ]

Ahhhhh Thanks Dave. Really. Never thought to try searching that way. Sweet.

[C&T2]

Maybe I'm mistaken, but this looks like fibreglass to me, no? It doesn't look like the other HDPE tanks I've seen - certainly not like the grey water tank I have...







So, here is where the problem lies - I've cleaned the area up a bit since I took the photo. I removed all of the old rubber-ish stuff smeared all over, which I'm guessing was a PO attempt at sealing the leak. The black ABS pipe is inserted right into the tank. There is a fair amount of wiggle room for the pipe, and it even turns slightly, but when I've tried to pull it back out it feels like it is stuck on something...





I think I'll do some more work on it this weekend to get a better view of what exactly I got going on here. I like the idea of the flex-joint Dave, but as you can see there isn't much of a flange there at the moment. There are some notes in the first link of LJ-TJs that might help me along once I get this cleaned up some more.

[Rickf1985]

What you are looking at is definitely fiberglass but is that the actual tank or is it a cover over top of insulation that is covering the tank under all of that? No matter what, you need to work back further along the pipe until you get to a solid surface to repair from. You will never be able to repair a leak working with what is showing there.

[Jerry]

How do I disconnect the drain for the grey tank? It looks like 2 lines going into the tank. Trying to get a pic to load but keeps saying it is to large and it is only 250 kb