ACDelco 18M2558B Gold Brake Master Cylinder Assembly with Reservoir

The ACDelco 18M2558B is a Gold-line brake master cylinder assembly engineered as a high-quality replacement for OEM brake hydraulic systems. ACDelco Gold (formerly Professional) parts are manufactured to meet expectations for fit, form, and function, making them a dependable choice for General Motors vehicles and a wide range of other makes and models.

Key Features:

• Aluminum and iron castings provide a durable, high-quality construction that places no extra stress on the brake booster mounting
• EPDM and SBR rubber components — Ethylene Propylene (EPDM) and Styrene Butadiene (SBR) seals deliver superior resistance to heat, corrosion, and leakage
• Geometrical tolerances ensure the body and plastic reservoir align precisely for a leak-free, proper fit
• Piston assembly and return spring help prevent brake drag, reducing the risk of premature brake pad wear
• SAE J1153 and J1154 compliant — meets industry brake performance testing requirements for proven reliability
• Pressure tested before leaving the factory to ensure safe, confident braking performance
• Ready to bench bleed and install — no additional assembly required straight out of the box

This brake master cylinder assembly cross-references GM OEM part number 88875883. As part of the ACDelco Gold line, it is backed by General Motors and represents a premium aftermarket solution for restoring proper hydraulic brake function.