Black tank leak. Need advice.

[bobbyg123]

Hi everyone,

Well, I just discovered a dubious slow drip of my nearly full black tank, and I'm not sure how to proceed. Let me explain my situation.

I store my 5th wheel 300 miles away from home in a small town during the Fall and Winter, as we use it to tailgait for football games. I use a mobile RV dump company to drain the tanks every 2 games (approximately 5-6 nights), and with 4 of us staying in it, plus our party goers, the 30G black tank gets full quickly.

Today when packing up, I discovered a slow leak, not at the dump valves, but somewhere along the tank/vent pipe. I couldn't tell because the underbelly is sealed. The good news, if there is any good news, is that the underbelly isn't filled with waste water, so at least the issue isn't full blown nasty. I also detect a "sewage smell" in the pass through storage area, and I read somewhere that it could be another clue the vent valve is culprit.

My question is this....I'd like to examine the situation more closely and see if I can locate the leak, but that would involve me cutting the underbelly material to access the tank. Have any of you done that before?

The long term plan, after the fall/winter season, is to take the **** thing into a service center and have it properly fixed or the tank replaced, but I'd like to get some waterproof spray sealant and some tape on there if I could. I'm just afraid I'll butcher the sealed underbelly and cause even more damage and expense to the job.

[bobbyg123]

I called an RV repair mechanic that I trust today, and he advised me to leave it alone and just keep the tank under 50% until the offseason when I can either fully address the issue or take it in and have a shop take care of it.

Sounds like good advice. The tanks got drained today, so when I get there next weekend, I'll add a few gallons of freshwater to the black tank and see if the problem returns. If it does with just a small amount of water, I'll be forced to stop using the toilet for the rest of the season. Not easy when you're drinking beer before a game with a bunch of people.

Crossing my fingers that this is an issue related to a full tank.

[schlep1967]

Gorilla tape is your friend.
You can cut a 3 sided flap, leaving the side towards the front of the trailer attached, and pull it down to get a good look up inside. Then once you are finished make sure the coroplast is clean (as in use soap and water to clean it) and dry. Then apply the gorilla tape. It is usually easier to clean it before you cut it then do minor cleanup before taping.

Also, Get the tank emptied and rinsed as much as possible before you try to work on it or take it to a shop to work on it.

Best scenario is you had it really full and that pressure squeezed something out through a not so sealed opening. I would limit the bathroom use to family or watch the tank gauge (if it works) and cut off the bathroom privileges at 3/4 full.

[bobbyg123]

ssthrd wrote:
On my 5er, the coroplast underbelly is attached to the frame with a bolt every foot or so. When I had a tank issue, I unbolted the front and one side enough to have a look with a flashlight. I figured it would be better than slicing it open with a knife not knowing what I was going cut in the process.

Yea, that's a good point. It looked like my underbelly cover is stapled, so dropping it would be more of a pain. The bigger thing I'm debating is if it's even worth addressing the problem myself. Might just be better off keeping the tank less than 1/2 full and taking it into a shop in the offseason.

I don't know though. I hate to just leave it without at least trying a bandaid fix.

[ssthrd]

On my 5er, the coroplast underbelly is attached to the frame with a bolt every foot or so. When I had a tank issue, I unbolted the front and one side enough to have a look with a flashlight. I figured it would be better than slicing it open with a knife not knowing what I was going cut in the process.