BMW TSB #B360121
2019 BMW Z4
Affected Component: EQUIPMENT ADAPTIVE/MOBILITY
- Summary
- Diagnosis of Compound Brake System Complaints in M Vehicles: 1. Visible cracks are caused by high thermal stresses during rapid heating and cooling of the brake discs. Braking from high speed with cold brake components (less than 212 degrees F) increases the likelihood of cracks to form.