My 82' 380SL has developed the loudest break squeal that I have ever heard. It only happens after the car has been driven for a while and it is the loudest when the pressure of the breaks is about 50%. Slight pressure on the break pedal will not cause much if any break squeal. The same goes for hard pressure on the break peddle. At normal pressure on the break pedal they make a very loud and is embarrassing to say the least. Also if I go in reverse and stop quickly this seems to make the squeal go away for a short period of time.
Is there any thing that can be done for this? I had the pads checked and they are not worn or have any visible problem.

Thanks