Robbie ... my comment re the Harley was just regarding how it was viewed in period ...... in fact even back then I flushed it out and changed to DOT3 purely to have the same fluid on all my various vehicles for convenience (no detriment noted by me either when pushing out DOT5 with DOT3 .... just noting how perceptions change.)
The 'fluffy concrete' reference may not travel beyond the UK where we have an issue with a '60s form of aerated concrete in public buildings that was a 'wonder material' that has now turned out to not age well and causing closures and miilions in emergency repairs.
I have no doubt that DOT 5 used appropriately is a perfectly fine brake fluid.
K
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