Lazy Daze Owners' Group

We own a 2015 27MB.  Today the black tank dump piping fell off the tank.   Nothing seems to be broken and it seem I should be able to clean it all up and reattach the piping to the tank.   There were two hose clamps on the connection, but I don't see any evidence of any sealant/caulking/glue.  Is there an appropriate/necessary product to cover the mateing surfaces?

Also there was no support structure for this pipe run and the dump valve at the end.  Has anyone added pipe supports?  If so any advice on what might work?

Thanks
Geoff

The answers are yes and yes! Should be sealant and support. With that recent vintage, I’d give the factory a quick call and get current best practice.

That's a bit disturbing!  Agreed, I would call the Mothership. Might want to send a photo to Todd so he can see for himself.  Please let us know the resolution in this thread.  Now I better go inspect mine since it's the same vintage MB.

It could be that the tank is Polyethylene and the pipe is PVC. 

That's a hard connection to make with sealant.  Mechanical connections are commonly used.

Rich
 

The earlier MBs black tank PVC pipe/valve did not have a support system.   For example, our ‘09 MB is just as described by Geoff.   I’ve removed the valve several times for different reasons.  The first time, there was some kind of sealant, which I cleaned off.  Now, I simply use the two (2) clamps with no ill effects. 

Sometime after 2009, the factory installed some kind of a support bracket, which they don’t sell.  I’m guessing this was a 2016 or later black tank modification.

Called the factory. They were surprised the pipe fell off.  It must not happen very often.

They recommended using an ABS pipe joint compound and hose clamps.  They did not recommend adding any kind of a pipe support.

Thus far the worst part of the job has been the clean up, it occurred at our campsite as we were attempting to attached the sewer hose.  The reattachment process looks like it will be very simple and straightforward.

Geoff

What exactly fell off? The valve or a piece of pipe? A photo would help.
The dumps valves are clamped and not glued, glueing would make replacement impossible. The may use a removable sealant to seal the valve, one application where silocne maybe useful, it doesn’t permanently stick to ABS.

Larry

If it were me, I'd add a support using plumber's strapping. This stainless steel strap (https://www.amazon.com/Stainless-strapping-Adjustable-Woodworking-Automotive/dp/B092CN53R7/ref=sr_1_17_sspa?dchild=1&keywords=plumbers+strapping&qid=1628010548&sr=8-17-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyMzBQMUtCWTkyUTlPJmVuY3J5cHRlZElkPUEwMDQ3OTI1MlRCRE5BTFlWWDQ2TCZlbmNyeXB0ZWRBZElkPUEwMjU5NzkwMzBMWUxMSVVTQUlXVyZ3aWRnZXROYW1lPXNwX210ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=) looks as if it might do the job.

The pipe (not the valve) fell off.  My first attempt at adding a photo, hope it worked.

Geof

Geof-

Our black tank outlet assembly came loose. After I put it back together I added a strap to the skirt. I debated doing so; without, the assembly moves as one with the tank; with a strap the assembly will tend to twist at the tank collar ( and potentially leak). In the end, the idea of not having the assembly come loose on the road again won. A dissatisfyingly-almost-unhelpful picture is here (https://www.lazydazeowners.com/index.php?action=media;sa=media;in=2772#viewitem).

We sold the coach shortly after, so I don’t know how well the fix worked.

I seem to remember using polyethylene caulk in the joint when reassembling it.

Mark H.

If you notice that the generator exhaust pipe uses a flexible rubber strap to support the pipes weight. It makes me wonder if a rubber strap similar to the exhaust strap would provide the support for the dump valve while not being “inflexible”.

Just a thought.

Kent

We had the same thing happen to us while camping in 2017 in our then new-to-us 2011 MB.  We were very fortunate in that the valve and piping fell off just after we had dumped and I was closing the valve.  We simply reattached using the existing hose clamps and were on our way.  We posted about the incident on the forum: Yucky story about dumping the black tank (https://www.lazydazeowners.com/index.php?topic=30918.msg179608#msg179608). 

After much consideration, we decided not to add a support because we think the support has the potential to do more harm than good.  Maybe this is the Mothership's rationale too.

OK...I think I'll go check those hose clamps now.

Jim

Well its all back together and has passed a leak test.  Decided against the support strap idea for the reasons mentioned above. 

Thank you all for your input and suggestions.    You all helped to keep our day from spiraling any further than it already had.  The failure happened while we were dumping, it was quite spectacular and MDW was in the splash zone, I'll leave it at that.

Geoff

The failure happened while we were dumping, it was quite spectacular and MDW was in the splash zone, I'll leave it at that.

Good to hear all is well now, Geoff.  I'm afraid if that happened to my DW, our RVing adventures would be immediately over so hats off to your bride;  you can both laugh about it now!  Now's a good time to pull this out of the vault for a little levity:

https://www.youtube.com/watch?v=-C0bpTLEmZw

Got under Nocona to take a close look at the black tank piping. It’s a very short run but I did notice a place where it looks like the factory had put in a support which is now not attached.  Wondering if I should reattach it?  Also, does anyone know the size of the hose clamp needed as I would like to have a spare on board just in case the existing one breaks?

"...it looks like the factory had put in a support which is now not attached.  Wondering if I should reattach it?"
---
Considering the potential for the pipe dropping/breaking, and subsequent spillage, re-bolting seems to me like a real good plan!  :o

Hi Greg;  That pipe up to the back of the gate valve is filled with liquid from the get go as you drive down the road. So that weight is trying to rotate and loosen the hose clamp fitting. I would put a rubber grommet in one of those holes and a SS screw through the center to support that, but not have a solid connection. 
   My old Emerald Onan generator has an external exhaust pipe with a rubber section attached to the skirt and the pipe. Of course the generator flexes and moves more than the black tank, but kind of the same idea. Speedway Poly Exhaust Hanger Grommet Bushings (https://www.speedwaymotors.com/Speedway-Poly-Exhaust-Hanger-Grommet-Bushings,46327.html?sku=91000118&utm_medium=CSEGoogle&utm_source=CSE&utm_campaign=CSEGOOGLE&gclid=CjwKCAjw092IBhAwEiwAxR1lRnBQElMLrvtY90LoPg1KSCeJDwlDb9x0rQKKaub88fG7oNgzIWwNRhoCNv4QAvD_BwE)    RonB

Thanks, Ron and Joan for your responses. I was able to find a rubber grommet to fill that gap in my parts and pieces bin and did a temporary fix until I can get down to Home Depot and get some stainless steel hardware.

I really like this idea.  I think I’ll add a second L bracket on the other side of the valve to share any stress from movement.  And do the same on the gray tank valve.   I believe I’ll add a nylon washers under the bolt heads too.  Again to reduce pressure on the fiberglass from the bolts.   Thank you for sharing the above pictures.  

You're welcome, Ed!  You may not need to do anything to the gray piping if it's anything like mine.  I checked it out when I was fiddling with the black valve and the gray piping appears to be mounted securely in two places before going into the tank.  Let us know what you find!

Corollary to supporting the dump lines: check the tightness of the mounting bolts for the black and grey tanks.  ;)

Corollary to supporting the dump lines: check the tightness of the mounting bolts for the black and grey tanks.  ;)

Dang, Joan, now I have to make another trip under the RV!   ;)

Just trying to be helpful!  :D

Tightening the hose clamps that hold the dump valve's plumbing to the holding tanks is another thing to add to the annual maintenance list.
For an extra secure and leak-proof job, coat the inside of the connection with Goop or one of its variations, such as E6000, available at any big box hardware store.
Amazon.com: Amazing Goop 140211 3.7 oz. All Purpose Adhesive, Clear : Arts,... (https://www.amazon.com/Amazing-140211-Purpose-Adhesive-Clear/dp/B008AF1NHQ/ref=sr_1_1?dchild=1&keywords=Amazing+Goop+140211+3.7+oz.+All+Purpose+Adhesive%2C+Clear&qid=1628998802&sr=8-1)

Larry

I really like the rubber bushing solution.  Looks like a winner.
Dave

We own a 2015 27MB.  Today the black tank dump piping fell off the tank.   Nothing seems to be broken and it seem I should be able to clean it all up and reattach the piping to the tank.   There were two hose clamps on the connection, but I don't see any evidence of any sealant/caulking/glue.  Is there an appropriate/necessary product to cover the mateing surfaces?

Also there was no support structure for this pipe run and the dump valve at the end.  Has anyone added pipe supports?  If so any advice on what might work?

Thanks
Geoff

Mine fell off who knows where. Put the new one on without sealant. Just a hose clamp and there are no leaks at all. I check it often and used large zip ties to "catch it" if it falls off again. Remember that the valve clamps over the tank outlet, rather than in the outlet.

I noticed same problem on my '17 mb. Had been attached to the fiberglass panel but that did not hold. I added 2 narrow aluminum strips - one on each side of the fiberglass for strength and then reattached the end of the black pipe. Fix done in June, 2018, with 12,000 miles. Now almost 28,000 miles with no problems.

....... I added 2 narrow aluminum strips - one on each side of the fiberglass for strength and then reattached the end of the black pipe. Fix done in June, 2018, with 12,000 miles. Now almost 28,000 miles with no problems.

The one downside as I see it to this 'repair' is that if you  ever hit something it will take out both you black tank piping and you fiberglass.   Just something to keep in mind ......  I had a Ford Dealership take out my black tank pipe during a oil change.

glen

How high off the ground (or the distance between the ground and the pipe) is black tank dump piping? Do some models/years have different measurements?

Different years and different models have varying tank sizes, piping, and dump termination valve configurations and locations. Also, these elements may vary among years of the same model, e.g., the dump termination valves of the black and grey tanks on earlier TKs are separate; model years after 2016 (?) have a single termination valve for both the black and grey tanks. This piping and valve configuration is low-hanging and appears vulnerable to being snagged and ripped off; owners of late-model TKs might comment whether this has been a problem.

YMMV.

How high off the ground (or the distance between the ground and the pipe) is black tank dump piping? Do some models/years have different measurements?

What Joan said.  In my case, there is about 8" of clearance for the black valve.  The grey is less at 7" and is probably more vulnerable due to it's location rearward of the back tires. That reminds me, still need to order a spare Valterra valve!

Corollary to supporting the dump lines: check the tightness of the mounting bolts for the black and grey tanks.  ;)

Did this today and it’s now on my annual maintenance list (thanks for the tip!).  For those that want to do this, for both tanks, you will need a 9/16” wrench, and 9/16” deep socket, although YMMV.  I used a 5/16” nut driver to check the hose clamps.

I noticed same problem on my '17 mb. Had been attached to the fiberglass panel but that did not hold. I added 2 narrow aluminum strips - one on each side of the fiberglass for strength and then reattached the end of the black pipe. Fix done in June, 2018, with 12,000 miles. Now almost 28,000 miles with no problems.

I like this idea and may adopt it in the future, or at least add a second mounting bracket but, for now, just upgraded the hardware to SS.