"Jim Wilkins" writes:

...

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It's difficult to create innovative mechanical solutions with only
stock parts meant to solve standard problems. At Segway which was an
engineer's playground by official policy the CNC lathe and milling
machine were almost always tied up making someone's wild idea. I used
their manual lathe or my home shop machines but my main task was
custom electronics.

https://news.yale.edu/2008/12/05/stu...orrell-s-class
Electric model airplanes were practically a second product there, and
they taught me the care and feeding of Lithium batteries.
Unfortunately like bridge building the team dissolved and sought new
challenges once the project was complete.
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Maybe the "hydraulic fluid" could be grease - thick - tranmitting to
oil or water through a rubber membrane. So the piston/bush sees
viscous grease not thin oil.

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It's known that high pressure oil seals work if done right, so I'd bin
that with the minor issues that can be solved later by throwing enough
money at them, and concentrate on identifying and resolving the
show-stoppers.

I'm glad I read the Amazon reviews before applying the thick black
tire bead sealer goop. A reviewer advised to let it set somewhat
before inflating the tire lest it spray out. I did, and only soapy
water rubber lube sprayed me before the bead seated when I inflated
it.

Here is a racing engineer and technology historian who might know
about metal fatigue in oil:
https://www.calum-douglas.com/

Off-topic but...

Two
great leads in there!

Engine Development and how done.
Empires were at stake then and technical folk got resources - amazing
what they did.

The Calum Douglas lead - never met or seen a pic. of the brittle lacquer
method for stress distribution in-action. ****! it's effective!
The "perspex / polarised-light" method - I wanted to use that when I
knew a Finite Element Analysis modelling engineer must be talking
...nonsense!..., before I could FEA. I actually blagged some
"perspex" from a nearby company - but the Finite Element Analysis
engineer then made such a bad political slip-up that we lost the job
it was for anyway.

"Yale" / Segway lead...
The one about engineers "kissing a lot of frogs to find a
prince". Exactly! Yes, that's the reality of a scientist too!
You have to be able to think and process things that way, to be a
human having an effective channel of perception into the Natural
World.
I almost envy people living in what they think is a determinate world.