I heard an admittedly second hand story about a guy who'd had a rear brake seal fail. A mechanic friend came to the rescue and cut the brake pipe, folded it and squashed it flat so it would hold pressure. This was OK(ish) to get home just on the front brakes if driven cautiously, then he could take it to the garage to fix properly on the Monday. They met up a couple of weeks later and to the mechanic's utter horror, the guy said "Thanks for helping me out the other day. I've managed to sell the car "
PS for the avoidance of doubt, this is not a recommendation !