The brake system undgoes much severe torque impacts from engine, hydraulic system or uneven terrain grounds.This often leads to unpleasant vibration.noise and sometimes friction disc failures.In the paper the whole brake system was modeled which consisted of friction discs.stainless discs, cylinder, ring gears etc.with CAD models.Many contacts such as gear meshing and disc friction contacts are defined, because of the large amount of computation with contacts.