First off, I am not an expert. I took on the job only after checking the operation of another smaller dishwasher that was not working correctly.
That dishwasher is a portable Danby dishwasher, and some of you may be familiar with them. That dishwasher only needs a seal to be fully operational, the part itself is no longer available, but, I do have an answer and a close enough replacement that will do the same job.
This dishwasher that I bought parts for belongs to my landlord, and we have an arrangement.
"Under the title, what was the problem". water pump operating even when empty.
The dishwasher was operating the pump because the float was no longer set right, the float (foot), sits on a switch that tells the computer when the machine is full of water. The float foot was missing the switch and allowed the switch to be closed at all times, the switch is under the machine, so you may need to remove a panel under the door to gain access to this area.
You can manipulate the float, or have someone else do it to see what I mean.
On this machine, what I found was that the float keeper had become warped due to what I expect was heater operation, and the plastic eventually slipped, and would no longer keep the float oriented properly.
I removed the float, and the switch from this bracket. I then removed the bracket from the machine. (See tools). After examination of the part, I applied heat to it, "where the hinge is that keeps the float foot in orientation", and bent the plastic a good amount.
{{{{{{{SUPER GLUE WILL WORK, BUT DON'T}}}}}}}}}}}}}
Yes, I did think to use super glue and be done with this, however, using super glue will never allow the float to be installed or removed.
I was fortunate in in that, I applied the right amount of heat, and pressure to bring this bracket back to proper orientation.
If this did not work, my backup plan was to use small grade wire, or even a zip tie to keep the float foot where it needed to be.
I figured all this out while the plumbing I had removed was sitting in a bath of CLR, because most of what I found was calcium deposits throughout.
I bought the fine mesh filter because I could not clean it, the docking station was worn to the extent that it would not seal.
CONCLUSION.
After replacing the parts, I ran the dishwasher through a full cycle, (no dishes) substituting dish soap with CLR.
Landlord is quite content after repairs completed, It does not run brand new, but runs better than it has in years.
Under tools I listed other, other is torx bits ranged t-15 to t-25, plus 1/4 inch ratchet 1/4 inch deep socket, you may use or need instead a shallow 1/4 socket with extension.
I hope this explanation helps anyone who, like my landlord, does not want to spend money replacing a dishwasher.
Total repair in parts, less than 100 dollars.