It would be interesting to see how the 5.1 fluid is holding up with regard to moisture.
The consensus (at least that I've read so far) is that in exchange for the higher boiling points of 5.1 vs 4 vs 3, you need to increase flush frequency due to the increased hydroscopic nature of the fluids. I've got a digital tester on the way so am tempted to compare 3 vs 4 vs 5.1 with respect to moisture uptake. Usually with automotive tech, particularly engine oil, switching to newer tech is a good thing with no downside. WIth brake fluid, the situation may be different.
My thinking is this. If you're driving a LEAF, the higher boiling points won't be in issue unless you're racing or descending mountains. However, if the fluid has a higher affinity to absorb moisture (and you're not doing yearly changes) then you may actually be exacerbating corrosion likelihood with fluid that retains more moisture. If you're flushing yearly, then I would assume 3, 4 or 5.1 won't matter.
One thing I did notice on the 5.1 spec is lower viscosity at very cold temps, which in my case is not a bad thing. Nub[/b], does your LEAF see temps below -10 C? Just curious if you notice anything different with respect to pedal feel or any ABS/stability issues in cold ? My spidey sense on the large difference in viscosity (cold temp) between 3 and 5.1 is that if anything it should increase ABS performance at very cold temps, not hurt it.
I have a Motive pressure bleeder, but just sourced a Speedibleed system specifically because they have a pressure cap that fits my 2018 LEAF reservoir.
Does anyone see a point to shoot a quick video on the system? I do our vehicles pretty much every 2 years now so having a pressure bleeder on hand makes the job a lot quicker/easier working alone. Bleeding via vaccuum at the calipers, or any method that uses the bleeder screw in negative pressure does not completely evacuate air in my experience. Been at this for a long time too