I have a rear disc brake noise when I apply the brakes.

What is your question?

This only happens once the brakes are hot. Have put two sets of rotors on, re-machined them, several sets of pads, semi metallic and ceramic and replaced a caliper (reman). If I gently apply it doesn't make a sound. But when I apply the brakes normally it happens. Almost sounds like a over stretched spring noise, if that makes sense. Not sure where to go from here. Driving me nuts....