I did one tonight actually. I knew i had a leak, but couldn't pin-point it. So i finally did a test. it was at the 2nd coupling on the hot pipe, the tbolt clamp had loosened itself.

All Brandname Turbonetics Couplings and Tbolt Clamps, and i still have leaks from time to time. Its not always about "quality products", Things happen, cars wear down, air finds ways out after time.