Update: Replaced the rotor and cap, runs better.
Determined the yellow flakes were from the sly-glyde that had dried since installation about 9 years ago.

__________________
1991 300E 124.030 103.983KE 722358 03 412178
207K

1979 240D 123.123 250K (Project car)

2000 Ford Ranger, 187K

2015 Dodge Ram 1500 EcoDiesel 37K