ACDelco 18B536 Professional Rear Brake Drum: Automotive. Buy ACDelco 18B536 Professional Rear Brake Drum: Drums - ✓ FREE DELIVERY possible on eligible purchases. Inspected for balance; resulting in smooth brake operation and noise reduction . Independently tested with Noise/Vibration/Harshness (NVH) and durability/wear testing; resulting in high quality and reliable products . Follows original manufacturers' designs for dispersing heat, helping to prolong pad and rotor life while reducing noise and vibration . Professional Brake Drums are constructed with G000 SAE qualified material for structural integrity and maximum service life. They are tested to ISO/TS 949 quality system standards and validated for balance to provide better braking performance. Chamfer angle, vane configuration, and plate thickness all follow the OE design, making them the ideal premium aftermarket replacement for your GM and non-GM vehicle. Also, no machining is required. Professional Brake Drums are ready to be installed right out of the box. . . .