Check the brake pads for wear and fade.
Check the brake disc for damage and cracks.
Check the thickness of the brake disc and run-out using a micrometer and a dial gauge on the part dotted line in the illustration below.
Brake disc thickness
Standard: 11 mm (0.43 in)
Service limit: 9.4 mm (0.37 in)
Deviation: less than 0.01 mm (0.000039 in)
Run-out
Standard: 0.03 mm (0.00118 in) or less