BOSCH brake disc (0 986 479 B27) is precision-machined from high-grade grey cast iron for uniform heat dissipation and resistance to thermal cracking under heavy braking. Key dimensional data — Height [mm]: 27, Rubber mm, Brake Disc Type: Carbon, Brake Disc Thickness [mm]: 20, Rubber mm, Minimum thickness [mm]: Composite, Cast Iron mm — ensures the rotor geometry meets OEM tolerances for run-out, thickness, and parallelism right out of the box. Direct replacement for OE references: 09 4987 10, 09 4987 20, 09 4987 21, 09 4987 24 and 95 more. BOSCH rotors are checked for surface hardness and dynamic balance before dispatch, keeping braking distances predictable throughout the service life of the disc. Brake discs generally last 50,000–70,000 miles, though this varies with driving habits, terrain, and pad compound — heavy urban driving or towing shortens disc life considerably. Warning signs of worn discs include visible scoring or lip formation on the friction surface, vibration through the steering wheel under braking, and a persistent grinding noise even with new pads fitted. Disc replacement is an intermediate DIY task; you will need a torque wrench, a breaker bar (some hub-to-disc retaining screws seize over time), and a jack with axle stands — budget 1–2 hours per axle. When selecting brake discs, check that the disc type (vented or solid) matches the original, and look for a protective anti-corrosion coating on the hub and non-friction surfaces to prevent rust jacking. Always replace discs in pairs (both sides of the same axle) to maintain even braking balance, and bed in new discs with the manufacturer's recommended gentle-braking procedure for the first 200 miles. Every part is dispatched with tracked delivery and a 14-day money-back guarantee with hassle-free returns.

Robert Bosch GmbH, founded in 1886 in Stuttgart, Germany, is one of the world's largest automotive parts suppliers. Bosch specialises in braking systems, fuel injection, spark plugs, alternators, and electronic engine management. As an OE supplier to virtually every major car manufacturer, Bosch parts meet or exceed original equipment specifications. With over 130 years of engineering innovation, choosing Bosch means choosing proven reliability backed by extensive research and development.