I wanted to make sure that I had got the sender unit as clean as I could. I bought a set of security bits that had several two pronged driver ends and took the little screw at the bottom of the sender off.



Here you can see that even just under the bottom washer there is a load of crud that unfortunately could not be shifted other than by disassembly.

Here the outer casing is being pulled from the end with the electrical plug



You can clearly see the three delicate wires...

And here is a picture looking down the tube. Muck.



And this one is showing how much muck I had to scrape out of the bottom.



It is all cleaned out now and back together. It really is a 10 minute job.