Probably of no interest to anyone but me, but I just can't stop taking things apart.

 

Hi dh53,

Kindred spirit...... good on you for satisfying your curiosity and sharing.

Spent my entire life pulling things apart to see how they work, which started when I was about 7 years old. I only recently found out my dearly departed father used to 'seed' his workshop rubbish bin with curiosities for me to find and work on after school. Sly old bugger!
He served his apprenticeship as a motor and generator rewinder, then 40 years running his own electrical contracting business doing both industrial and residential work.

For what it is worth, I agree that there certainly looks like some brush chaffing from the carrier that seems to indicate vibration of some kind occurring and likely eventual failure of the braid. Usually lack of supportive depth of brush still engaged inside carrier.
Scenario 1 would be the case if the Tinsel wire has collapsed the normally open weave along its entire length and the commutator end of the brush and commutator would normally both have some evidence of intermittent contact arcing (not normally a good thing in a petrol tank!).

Is it just me.........but I really don't get the idea or benefit of in-tank fuel pumps, just seems an unnecessary risk....what was ever wrong with a good old inline external pump and just an inert pickup and coarse filter in the tank?
Following that design logic, I might as well develop a 2 pack a day smoking habit if I was to work at a propane filling station, or go underground coal mining with a open flame headlamp! ;-)