Only had total brake failure twice ... coming down Mam Tor towards Edale in a recently purchased and decidedly dodgy Vauxhall Victor ... remember my Mum and Sister chatting oblivious in the back as I white-knuckled it through bends thinking we were all going to die! 🙂 ... previous owner had used motor oil in the braking system and every seal was mush.
Second time was coming down off the Atlas Mountains in Morroco in the summer in a Citroen Dyane ... seemed like 100 miles of steep downhill in pizza-oven temperatures ... was glad that the outside of a big bend at the bottom was a smooth run-off into miles of desert! ... by the tyre tracks I was far from the first to be grateful for a mile or two of sandy run-off 😀
That's the only (and very extremely provoked) time I've had boiling brake fluid in millions of miles of driving (but then I've owned multiple land-rovers that have been faultlessly reliable so maybe guardian fairies visited my crib as an infant 🙂)
K