2009 Suzuki 400 LTZ Quad Sport Service Manual, Page 397Get this manual
4C-10 Rear Brakes:
Rear Brake Disc Inspection
Brake disc thickness Inspect the brake disc for damage or cracks and measure the thickness using the micrometerReplace the brake disc if the thickness is less than the service limit or if defect is foundSpecial tool (A): 0990020205 (Micrometer (0 25 mm)) Brake disc thickness Service limit (Rear): 3.5 mm (0.14 in)
B933H24306008
I933H1430042-01
3) Remount the rear brake caliperRefer to "Rear Brake Pad Replacement (Page 4C-2)"(A)
Rear Brake Disc Plate Housing Inspection