ACDelco 18M973B Professional Brake Master Cylinder Assembly

The ACDelco 18M973B is a professional-grade brake master cylinder assembly engineered as a high-quality replacement for a wide range of vehicles. Built using a combination of aluminum and iron castings, this master cylinder delivers the structural integrity and precision tolerances required for reliable, long-lasting braking performance.

Key Features:

• Dual-material construction — aluminum and iron castings ensure proper fit, form, and function
• EPDM and SBR rubber components — Ethylene Propylene (EPDM) and Styrene Butadiene (SBR) seals provide superior resistance to heat, corrosion, and fluid leakage
• Precision-machined body — geometric tolerances ensure the cylinder body and plastic reservoir mate correctly for a leak-free seal
• Piston assembly and return spring — designed to help prevent brake drag, which can lead to premature brake pad wear
• Bench bleed ready — comes ready to bench bleed and install straight out of the box with no additional assembly required
• Includes reservoir — complete assembly with fluid reservoir for a straightforward replacement

ACDelco Gold brake master cylinders are manufactured to meet rigorous OE-level quality standards backed by General Motors engineering. The 18M973B is sold as an individual unit and is designed to restore proper hydraulic braking pressure and pedal feel to your vehicle's braking system.