In the Bahrain GP, Fernando Alonso had to withdraw in the 33 laps, but… Why had he to stop?
A sandwich wrapper was to blame when it got stuck the ventilation system of the rear brake. It caused an overheating that damaged the brake system. The pit crew realized about this overheating and they opted to withdraw for the safety of Alonso and the others drivers.
When the air intakes of the ventilation system is obstructed, the temperature of the disc and pads increase. It would cause the friction material would burn, the brake fluid would boll and the disc would erode, even there can be explosion risk.
For more info, please visit: https://www.brembo.com/en/company/news/f1-single-seater-brake-ventilation