I was considering like a line burst but yeah, ur correct, at least front/back is separate for sure
Yeah, if a line bursts you still have some brakes. I believe it's front right and rear left paired and front left and rear right, actually.
However if the master cylinder cracks or fails, i guess its possible to instantly lose breaks?.. but again it'll stay broken after...
I suppose, but seems highly unlikely. That'd be an insane failure. It'd also be incredibly messy any obvious. And you're right, would be incredibly obvious because it'd remain broken. Also, the logs would clearly show brake presses in this case since the brake switch is not even part of the iBooster.
I've never seen any fail in such a way. Have seen iBoosters survive some incredible accidents unscathed. I can't imagine them just self-destructing.
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Random, but funny: