Black tank leak on seasonally parked 5'er

[PokerCamper]

After buying our 2012 Keystone Cougar 26SAB used in 2014 for a great price, we traveled around for two seasons before this year deciding to park it for the season at a semi-local campground. We struck gold and made all sorts of friends, so we're staying, probably for a few years.

A couple of weeks ago, I noticed a slow drip underneath the RV and when I got down there, could tell the water was blue from my black tank chemicals ... bad news. I tried sealing it up with RV aluminum roof tape but wasn't really surprised when it didn't hold.

It's leaking from a barely perceptible crack around the center end drain hole and there's also a very slow leak from the valve. The valve is relatively new, replaced by the dealer in the spring of 2016 when the galley grey was replaced under extended warranty. My first thought was that they screwed up the valve replacement and cracked the tank. Sadly, the warranty has expired and even if it was active, I don't want to haul it out of the campground after we just got everything set up the way we want it this season.

So my options are try to seal the leak in some way or find a mobile repair guy to install a new black tank and valve on site. There are a couple of certified RV repairers in Vermont that I can call but I first thought I'd check with everyone here to see if there's a way I can DIY it to stop the leak. If pictures are necessary, I can do that next weekend when we're back down there to begin winterizing it, but if I can't repair the leak, my antifreeze is just going to run out and the tank will be dead on arrival next spring anyway.

[PokerCamper]

Keily wrote:
I don't know if this will help you or not, but it may help. I have helped an RV tech replace 2 black water tanks on 2 2012 Palamino 5th wheel trailers ,in the same campground, in the same season. What we discovered there was a hairline crack at the very top of the tank corner. It would only leak when the tank would get full and as long as the owner dumped every few days there was no problem.

Thanks, this is exactly what's happening with my tank but mine starts leaking as soon as it holds four or five flushes. The dripping just gets stronger the more full the tank gets, but as soon as I open the valve to dump, it slows down dramatically.

I'll try sanding the area down and applying the JB WaterWeld epoxy putty to see if that works.

[PokerCamper]

Thanks for the suggestions folks, I appreciate it. I presume you're talking about JB WaterWeld Epoxy Putty? I've used their metal product before to fix a defect in my Blackstone Griddle so I'll get some and give it a try.

[Campfire_Time]

Another plug for JB Waterweld products.

[Dave_H_M]

If you get that crack dried out completely and rough it down with say 220 sand paper and then get the JB on with a good coat, I bet your problem will be solved.

[SteveB]

I have used regular black ABS cement and fiberglass cloth to fix the bottom of an old cracked black tank. It worked great until the top started leaking the next year. Then it was time for new.

[Keily]

I don't know if this will help you or not, but it may help. I have helped an RV tech replace 2 black water tanks on 2 2012 Palamino 5th wheel trailers ,in the same campground, in the same season. What we discovered there was a hairline crack at the very top of the tank corner. It would only leak when the tank would get full and as long as the owner dumped every few days there was no problem. Anyway, the RV Tech checked with the manufacturer of the old tanks after the second one and he got them to replace the tank free of charge. So that would make one think that the manufacturer may be in someway may be admitting that there may have been a bad batch of tanks produced that year. Just something you may want to check into in case this may apply to you.

Good luck

[steveksfc]

I can say yes to the JB Weld for plastic. Used it on the outlet joint on grey and black water tanks that started dripping while camping over Memorial Day weekend. Dried the tanks out for a few days then applied the JB Weld. Since then we have made several trips and even had the tanks full before dumping and so far no more leaks.

[Nutinelse2do]

Carl n Susan wrote:
This is the hot ticket for repairing cracks in ABS tanks. Plasti-Mend ABS Plastic Repair Kit for Holding Tank Repair"

Clicky

We tried this stuff, and it didn't work, even after 5-6 coats. Yes, we applied it correctly.

[shadows4]

Years ago I used regular old JB weld on a plastic fuel tank in a car. Held for two years we had it after the repair. Worth a shot if you ask me.

[FF286]

I have used JB weld for plastic on many items. Since the camper won't be moving it may work. If you will be moving the camper any I'm not sure how it would do.

[Carl_n_Susan]

This is the hot ticket for repairing cracks in ABS tanks. Plasti-Mend ABS Plastic Repair Kit for Holding Tank Repair"

Clicky

[Bumpyroad]

on TV I see some magic tape that you can slap on over a hole in a water tank and it will seal?
bumpy

[darsben1]

see previous 2
But the tank does not need antifreeze and it should be the same as you left it

[laknox]

What he ^^^^^ said!

Lyle