During a drive from North Carolina to Kingston, Ontario in 2009 for the annual Austin-Healey Club of America Conclave, I experienced brake failure. As I was braking for traffic ahead about 30 miles west of Montreal, I suddenly felt the brake pedal continue slowly toward the floor. After grabbing the hand brake to stop and getting off the road, I discovered that the upper leaf on the right hand rear spring had broken and the broken end had trapped the hard brake line against the rear axle housing and cut it. Brake fluid was dripping off of every surface! I suppose the atrocious condition of the two-lane roads in New England was responsible for the broken spring.
Using a pair of vise grips, I curled over the broken upstream end of the brake line and then peened it flat using the ballpeen hammer in my tool bag and (for an anvil) a piece of square metal tubing I found at an abandoned service station nearby. This sealed the system sufficiently to allow me to drive on the last hundred miles with three hydraulic and one hand brake. After I arrived at Conclave, I found a handy repair service set up in the parking lot of the hotel, at which the mechanic made me a new flared brake line on the spot.
The remaining problem was how to strap down the broken leaf so it wouldn't cut the new line. I tried several different solutions, all unsatisfactory, until I hit on the idea of splicing together two radiator hose clamps for a strap. I didn't expect this repair would last more than a hundred miles before the hose clamps would break as well, but to my surprise it lasted almost 4,000 miles until I replaced the set of springs.