Bleed Screw M10x30 ABC303

A bleed screw (or bleeder screw) is a small, threaded valve located at the highest point of hydraulic systems—commonly brake calipers, wheel cylinders, and radiators—used to purge trapped air and old fluid. By loosening this screw, pressure forces air out, replacing it with fluid, which restores firm pedal feel in brakes and prevents overheating in cooling systems.