Unscrew the three bolts M12x1.5 and fix the hub in a vise using aluminum plates (see fig. 251).
Pic. 251. Removing the brake disc.
1 - hub,
2 - socket wrench with extension,
3 - brake disc.
Using a socket wrench with an extension, unscrew the self-locking bolts securing the brake disc to the front wheel hub.
Check the wear of the working surfaces of the brake disc; if grooves with a depth of more than 0.5 mm or cracks form, the disc must be replaced.
The brake disc is installed in the reverse order, tighten the new self-locking mounting bolts. Install the hub on the pivot pin and check the runout of the outer working surface of the brake disc, as shown in Fig. 252. With a large amount of runout, it is necessary to rotate the brake disc relative to the front wheel hub. Install the caliper and, if necessary, bleed the air from the hydraulic brake system.
Pic. 252. Checking the runout of the brake disc.
1 - brake disc,
2 - indicator mounting stand,
3 - dial indicator