Attention! Composite brake discs cannot be processed.
Brake discs are always ground on both sides of both wheels for one axle, observing the roughness (purity of processing) working surface – 0.5–3.5 µm and minimum front/rear disc thickness – 28.4/18.4 mm.
It is permissible to remove no more than 0.4 mm from each side of the disc.
Only one set of brake pads may be used on a disc of minimum thickness.
Remove the discs, grinding of brake discs must be carried out on machines (fig. 11.31) in the service station premises, strictly observing the machine operating manual.
Read the original source on the website BMWMAN.ru