SgtB

Find a welding supply shop and buy a spray can of prussian blue. Spray it on anything that spins and look for marks after a trip.

Disclaimer: be careful what you spray. PB usually comes of with soap and water, but don't spray it on anything pretty.

my2ks2k

sounds like a bearing to me. especially since it shows up with heat

INTJ

This is insane. Take the wheel off and spin the disk, if it hits the shield bend it back. If it doesn't hit, replace the bearing. For the shield to be bent enough to hit the disk, something serious was hit, if that actually is the case look for other damage.