leak from bathroom graytank

[Dave27]

I have a "periodic" leak that I suspect is from the bathroom gray tank. It shows up by leaking from around the low point water outlet. I only notice evidence of a leak after we have used the tank for several days after the last dump. After we took showers, the leak was there. This may not be the full story, but based on what I've observed, I suspect a leak starts in the bathroom gray tank after it fills to a certain point. How are these tanks constructed, what am I likely to find when I take down the chloroplast? Is there a fitting that could be loose, or a crack in the tank? I would like an idea of what to look for, and is it something I can fix, or will I need a specialist, or possibly replace the tank?

Any insights are welcome, I want to be prepared when I dig into this.
Thanks,
Dave

[Cate&Rob]

Dave27
Hi Dave,

First place to check is where the shower drain connects to the grey tank. On our 303, this is a common pipe for both vent and drain . . . and was originally "skewed" through the tank grommet. This is behind the aft wall in the pass through, so easy to check for signs of moisture.

Rob

[Country Campers]

Dave

Another place might be the tank level sensors. One at a certain height could have gone missing or unscrewed and making a leaking point at a certain level. It cold also be the exit drain on the tank. I have seen some of these attached with what looks like butyl tape paste , this could be a potential spot as well. It is kind of hard to prepare for this when it could be a number of things.

Brian

[TucsonJim]

Dave

Another place might be the tank level sensors. One at a certain height could have gone missing or unscrewed and making a leaking point at a certain level. It cold also be the exit drain on the tank. I have seen some of these attached with what looks like butyl tape paste , this could be a potential spot as well. It is kind of hard to prepare for this when it could be a number of things.

Brian

I had a leaking gray tank on mine also. Our leak was caused by a leaking sensor. The nut on the sensor was very loose. I was able to tighten it and stop the leak.

[Dave27]

Dave27
Hi Dave,

First place to check is where the shower drain connects to the grey tank. On our 303, this is a common pipe for both vent and drain . . . and was originally "skewed" through the tank grommet. This is behind the aft wall in the pass through, so easy to check for signs of moisture.

Rob

This was an easy place to start, thank you Cate&Rob for suggesting it. Everything is dry in that area, so the next stop is below. Thank you Country Campers and TucsonJim for suggesting the sensor. It stopped working, so maybe that is a clue too. I am going to wait a bit to dig into the underside.

Dave

[Dave27]

I found it! Attached are two pictures. It looks like the tank was damaged and someone at the factory tried to patch it up. The tank has to fill for a while before it leaks, once it reaches a certain level, it come right out. Any suggestions about what I can do with this? Cate&Rob TucsonJim Country Campers
Thanks, Dave

[TucsonJim]

Dave - That's a new one for me. I've never heard of the factory doing a repair like that. There is a product for repairing black ABS holding tanks that has a pretty good reputation. But I think you'd have to remove all of the old patching material before proceeding.

http://plasti-mend.com/cart/index.ph...=5b7872064037b

Jim

[Cate&Rob]

Dave27
Hi Dave

I'm amazed that "cobbled up" repair job lasted as long as it did. To patch a patch that is already that old would be difficult. For "peace of mind", I would be inclined to replace the tank. Probably the easiest one to R&R once the coroplast is dropped. One inlet and one flanged gate valve. The tank will be hanging on bolted-in support rails . . . although, at some point, Grand Design added straps under the tanks for additional support. This would be worth doing for the replacement tank, if they are not already there.

Rob

[TucsonJim]

If you want to replace the tank, let us know and we can help you with the correct part numbers.

Jim

[Country Campers]

I agree with replacing the tank. Trying to get that mess cleaned up good enough to hold a new patch would not be worth the effort.

Brian

[TucsonJim]

Dave,

Does this tank have a 1-1/2" side drain (LH), or does it have a 3" end drain?

Jim

[Cate&Rob]

I've never heard of the factory doing a repair like that.

Dave27


I would agree with Jim on this. Not that it matters at this point, but this looks like something that a dealer would attempt, rather that replacing the tank. The factory would just replace a damaged tank as their easiest course of action with production parts that they would have on hand.

Rob

[Dave27]

Dave27
Hi Dave

I'm amazed that "cobbled up" repair job lasted as long as it did. To patch a patch that is already that old would be difficult. For "peace of mind", I would be inclined to replace the tank. Probably the easiest one to R&R once the coroplast is dropped. One inlet and one flanged gate valve. The tank will be hanging on bolted-in support rails . . . although, at some point, Grand Design added straps under the tanks for additional support. This would be worth doing for the replacement tank, if they are not already there.

Rob

I see what you mean about the bolted in support rails. Would the gate valve have to be replaced, or just take it apart and put it back together with the new tank? And does the inlet have a rubber boot, or something similar that has to be replaced, or would it come with the new tank? It looks like you are right, it should be pretty straight forward to replace the tank. It would be a royal pain to get the old patch off and try to get a new one to work 'for a while". My philosophy is "water always wins." Sooner or later, unless properly designed and maintained, anything we use to contain water will eventually fail.
TucsonJim what do I need to do to make sure I get the right part(s)?
Thank you for the good advice.
Dave

[Dave27]

Dave,

Does this tank have a 1-1/2" side drain (LH), or does it have a 3" end drain?

Jim

It is an end drain, probably 3"

[TucsonJim]

It is an end drain, probably 3"

According to the GDRV parts lookup page for the 2016 27RL, that tank is a HT176B Holding tank. That's the same 43 gallon tank I have in my 2017 Reflection TT. It is a very common tank and readily available at several internet sales sites. I'd do a search for "HT176B Holding Tank" and you'll get quite a few options.

The tank is 28" Wide, 58" Long, and 8-1/2" deep.

Jim