Dorman M630559 Brake Master Cylinder with 7/8 In. Bore

The Dorman M630559 is a 100% new OEM-replacement brake master cylinder engineered to restore proper hydraulic braking performance. Featuring a 7/8 in. (0.875 in.) bore and dual M12 x 1.0 brake line outlets, this unit is designed for vehicles equipped with Vehicle Stability Control (VSC) and is fully compatible with power brake systems.

Unlike remanufactured alternatives, this master cylinder is built entirely from new materials, ensuring consistent quality and long-term reliability. The cylinder housing is cast to match the specifications of the original part, while all internal rubber components are made from high-quality EPDM compound for superior resistance to glycol-based brake fluids. The unit is manufactured to meet rigorous SAE International standards for safety and performance.

Key Features:

• Bore Size: 7/8 in. (0.875 in.)
• Outlet Quantity: 2 — both M12 x 1.0 thread
• Power Brake Compatible: Yes
• VSC (Vehicle Stability Control) Compatible: Yes
• Construction: 100% new — not remanufactured
• Seals & Rubber Components: High-quality EPDM compound for brake fluid resistance
• Housing: Cast to match original OEM casting material
• Standards: Meets SAE International specifications
• Country of Origin: Built in U.S.A.

Dorman's brake master cylinder line offers broad application coverage for repair professionals and DIY mechanics alike. The M630559 is a direct-fit replacement designed to restore your vehicle's braking system to factory performance levels without modifications.