While bleeding the brakes, pressure vanished and I found fluid squiring out on the front nearside tyre. A solid brake hose had sprung a leak. Odd because I had not done anything to it. On investigation it turned out to be an original steel pipe that had rusted through and fortunately burst in the drive. I had thought it was copper with a mess of underseal on it. Wrong: it was steel pitted with corrosion. I found one other steel pipe in the engine compartment in rather better condition, and replaced both. At 23 years old original steel pipes are an accident waiting to happen.