In brief: BW dump flex hose was assembled on 98° F hot sunny day - but the 55° water provided at Minnesota dump shrank plastics enough the hose just dropped off - The luckiest fellow in Minnesota is posting this story today!
A little back ground information: I purchased my 1973 '27 Overlander knowing PO was selling it w/ BW tank unclean - inches thick of tar complete w/ mold feathers with a few more identifiable deposits. The reek of formaldehyde was overpowering and I came close to walking away with that as deal killer. Drove straight home since I had no tools and didn't know if the plumbing was complete, etc. Very embarassing, y'all are the first I've admitted this to, shhh!
First thing when home - added water to drain traps, then put 20" box fan in window for positive pressure and w/ bathroom window open. I added a bottle of enzyme supplement horse-pills I've had around for years to the BW tank. Mashed about 60 of them up and dissolved in hot water w/ a couple of cups of sugar for wee-beasties & tanked it. Then stripped out carpet and cleaned for a couple of days - then went 2+ weeks with fan running while I had other things to attend to.
No leaks - I disinfected the grey lines (no GW tank) and tested the BW valve w/ momentary opening-closing, system looked good to try and purge the garbage from system. Odor was now a mix of formaldehyde and rotten papaya.
Got the AS ready on a 95° F sunny afternoon, meticulously checking clamps and cam-locks on 20' 4-inch flex line the PO had left. I removed bathroom screen and got my own garden hose ready and zoomed off to a county park w/ all-day $10 dump station pass & once there used a homemade side-jet blaster w/ curvey hose to scour year-old petrified tar sands and black hills from BW tank.
After 4th surge flush the white nylon tank bottom was visible (whew) and the corners inspected clean using a mirror-on-a-stick to view, so I then rinsed out of sink drains and bleached system, all in all using more water then the BW tank surges and a lot of clorox. Back outside, after wrestling the solids through the flex hose and a final rinse we shut the water off and paused to let it finish draining...
The DW and I were nearly dancing with glee the BW tank was CLEAN when... I looked down at hose to cam-lock clamp in time to see it settle a bit, wiggle and drop clean off! No water flowing, no one touching trailer or hose.. It just relaxed and dropped off! Since I was watching it when it happened, only a pint of clear clorox water was spilled before I could lift hose back onto fitting!!
Our ground water here in Minnesota can be 52-56° COLD which causes plastics to contract AND even allow a wrench tightened stainless steel hose clamp to slip around. My dump-station tool kit now has a 5/16" nut driver which WILL be used to check and recheck hose fittings the next several uses. I can not begin to imagine the nightmare that could've happened, or the reaction of motorhomes in line waiting to use the station...
Anyhow, thats my Alibi and I'm sticking to it