The black tank flush on my coach stopped working. Apparently this is a common problem, if the flush nozzles get gummed up with crud or water calcification.

One of the members of my Tiffin Allegro Bus 2016-2018 Owners group on Facebook did a post about fixing theirs, which was very helpful. So I embarked on this adventure too.

The hardest thing is getting to it. I needed to remove this panel from the side of the coach:

The right side is easy enough, with a couple of brackets and screws easily accessed with the adjacent basement door open:

But the left side was tricker, with no door there, so I needed to insert a screwdriver between two panels. To protect the paint, I wrapped the screwdriver shaft with painters tape:

Then inserted the screwdriver to reach the four screws:

That done, I was able to remove the panel:

The fresh water fill hose limited how much I could move the panel:

So I disconnected that too:

My little folding work stool was very helpful for this operation:

Let’s have a look around, since I don’t get to see this stuff often. Here’s the black tank; the green circuit board is the See-Level tank sensor, and the yellow rectangle is one of the two sensors for the rear toilet (the other is above that, obscured by wires):

To the left of the black tank is the gray water tank:

Below both waste tanks is the fresh water tank; the pipe in the foreground is the overflow and vent:

Pipes and wires from the bedroom and rear bathroom:

The horizontal-ish pipes are for the central vacuum system:

On the other side of that wall, a vacuum inlet and hatch in the adjacent compartment (we don’t use this vacuum; preferring to use a cordless stick vac):

Anyway, to business. Here’s the culprit, the “No-Fuss” Flush:

I removed it from the black tank; a bit gunky:

Cleaned up somewhat:

I tested it, but it still didn’t work very well, so I drilled out the holes a bit more (on the bottom and sides):

That solved it; the holes sprayed nicely.

To re-mount, I used plumbers putty to seal it:

And re-mounted it (the water is from testing it):

Then just a matter of re-attaching the fresh water fill hose and re-mounting the coach panel.

All better now. Hopefully I won’t have to do that again any time soon, but it wasn’t particularly difficult, other than removing and re-attaching the coach panel.