Checking the thickness of the front brake disc
1. Measure the thickness of the disc with a micrometer at eight points offset by 45 degrees and 10 mm from the edge of the disc (Figure 14.14).
Figure 14.14. Measure the thickness of the disk with a micrometer at eight points offset by 45 degrees and 10 mm from the edge of the disk
Brake disc thickness:
- Nominal value: 18.0 mm.
- Acceptable value: 16.4 mm.
2. The difference in disc thickness (at least in 8 places) should be no more than 0.015 mm between each of the measured points.
3. If the thickness differs from the permissible value, the brake disc must be replaced or reground.
Checking the brake disc runout
4. Unscrew the caliper support and secure it with wire.
5. Check the brake disc surface for pits, cracks and rust. Clean the disc thoroughly and remove all traces of corrosion.
6. Fix the dial indicator at a distance of 5 mm from the edge and measure the disc runout (Figure 14.15). The permissible value is 0.06 mm or less.
Figure 14.15. Checking the brake disc runout