I would think if the rotors are off this would happen every time but nope only occasionally , any ideas ? I am taking it in tomorrow but just a local type shop to get supercharger fluid done and a few small other things. Any idea of what to ask them to look at.

 

If it depends upon how hard you brake, then disks are a possibility. How old are the disks? If the ball joints, bearings, bushes etc are all good then I would probably change the disks and pads just to rule it out.

Richard

 

Could be a sticking caliper piston. If it only happens sometimes then it could be applying uneven pressure on the brake pads when the piston sticks, for example when it heats up and expands slightly.