ACDelco Professional DuraStop Brake Master Cylinders are manufactured to OE Specifications using both aluminum and iron castings. ACDelco master cylinders contain both Ethylene Propylene (EPDM) and Styrene Butadiene (SBR) rubber components to provide superior resistance to heat, corrosion, and leakage. ACDelco Professional DuraStop Brake Master Cylinders are ready to bench bleed and install right out of the box - no assembly required. Product Features:Meets the brake performance requirements of SAE J1153 and J1154Pressure tested to ensure safe and confident brakingCast iron and aluminum specifications; no extra stress on the brake boosting mountingGeometrical tolerance ensures that the body and plastic reservoir match for a proper fitPiston assembly and return spring help to prevent brake drag, which can cause premature brake pad wear
