When I back out of our driveway (sloped) or come to a stop somewhere the brakes on our 740 Turbo Wagon give me this springy, "boing" sound. The brakes will still work, even if it feels/sounds like they are failing for a moment. It doesn't always happen, but often enough to give me an uneasy feeling about the whole thing. This is our second Volvo with the exact same problem, but our mechanic isn't sure what it could be. I could have sworn I saw this discussed here somewhere before but hard as I try I can't find it again...thanks for any suggestions!!