Both rear springs broke. The bottom coils on both springs broke off. This does not sound like a coincidence, it sounds like a design flaw. It appears that the bottom coil is inverting and results in a torsional failure of the bottom coil, yes I am an engineer. The bottom coil is being subjected to excessive load and this results in a fatigue torsional failure. I would expect this to happen on a majority of these springs once sufficient cycles are accumulated. It looks like just over 100,000 miles these springs will fail!