We purchased Sassy in September 2019 in Los Angeles. Drove the two days back our RV spot in Brenda, AZ where we spent Labor Day Weekend. A great deal of effort was put into finding an RV spot near Flagstaff, but no we stayed in Brenda where it was 110deg through that holiday. Once the weekend was over we headed for Flagstaff. As we packed up we tried to dumped the holding tanks. The black tank would not dump which seemed to be a valve problem. Too hot to fuss with so we just headed north.

We stayed at Woody Mt CG in Flagstaff where we had a full hookup to straighten out the black tank problem. The black still would not drain. So, after a few go arounds on the Internet I figured out how to get at the black valve. On the Bigfoot, the tanks are enclosed and heated so they don't freeze, but this means you can't see the valves directly. There is a panel that comes off to get at the black valve.

After some caulk removal and a lot of screws the panel came off revealing the black valve. It is remotely operated via a cable and everyone though the trouble was in this cable. Well, I got into it far enough to verify the valve was probably functioning. On to plan two. I bought a small nozzle to go onto the garden hose (clean out/auxilary hose). Pushed this up the sewer outlet and shot some water towards the black valve catching the backflow in a bucket. I found the hose would push up to the valve, then when the valve was opened the hose would go further. Thus the valve works. SO, left the valve open, pushed the hose/nozzle through, and opened the faucet. This is dangerous without an empty tank, if the blockage lets go it will dump a large volume of "fluid" all at once. Started to get junk out through to the sewer outlet. Did this for some time until we were convinced the blockage was gone. No major gush of "fluid" catching and dumping bucket by bucket. I closed the valve, filled the tank using a clean out wand, and pulled the black valve. It flowed well, the blockage was gone. Ended up with many buckets of "fluid" dumped by hand down the sewer and about half a bucket of solid. Put the access panel back in place and started to feel better.

We figure the only explanation is the previous owner used the trailer in a trailer park for some time. That's OK but the problem comes from leaving the black tank valve open. This allows solids to build up in the tank. One should let the black tank fill to 2/3 or full and then empty all at once. This flushes the solid waste and keeps the tank working.

A week or so later, in Kanab, the back tank would again not drain. Figured the travelling loosed up more junk and blocked the valve. But now I knew how to go about a fix and had the right tools. A couple of hours work and it was running free again.

All in all, it took three days to track down the problem and fix it. A stinking mess but it's fixed.