Dorman M39457 Brake Master Cylinder

Reliable Brake Master Cylinder for Precise Hydraulic Control

The Dorman M39457 brake master cylinder is engineered to provide consistent hydraulic pressure for your vehicle's braking system. Designed with a durable cast iron construction and a 1.75-inch bore diameter, this master cylinder ensures reliable performance for compatible makes and models requiring precise brake hydraulics.

• Cast iron master cylinder material for durability and strength
• Includes reservoir for fluid storage and management
• 1.75-inch bore diameter optimized for effective hydraulic pressure
• Two outlet ports with secondary outlet thread diameter of 0.5 inches
• Rearward outlet size of 9/16-18 for secure brake line connections
• Package contains the master cylinder unit only; mounting hardware not included

Detailed Product Description

The Dorman M39457 brake master cylinder is designed to replace worn or damaged units in vehicles requiring a 1.75-inch bore diameter master cylinder. Constructed from cast iron, it offers enhanced resistance to wear and corrosion, contributing to long-term reliability. The included reservoir allows for proper brake fluid containment and management, essential for maintaining consistent brake pressure. Featuring two outlets, this master cylinder supports dual-circuit brake systems, with a secondary outlet thread diameter of 0.5 inches and a rearward outlet size of 9/16-18, ensuring compatibility with standard brake line fittings.

Common Applications and Issues Addressed

• Restores proper hydraulic pressure in brake systems with failing master cylinders
• Eliminates brake pedal sponginess caused by internal leaks
• Resolves brake fluid leaks from damaged or corroded master cylinders
• Improves brake response and safety in vehicles with dual outlet brake systems
• Replaces master cylinders with worn or damaged reservoirs to prevent fluid contamination

Installation Notes and Tips

When installing the Dorman M39457 master cylinder, ensure the brake system is properly bled to remove air and maintain hydraulic integrity. Verify compatibility with your vehicle’s brake line fittings, especially the 0.5-inch secondary outlet thread and 9/16-18 rearward outlet size. Since mounting hardware is not included, retain or source appropriate fasteners for secure installation. Follow manufacturer torque specifications to avoid damage during installation.

Quality Assurance and Warranty

Dorman manufactures the M39457 brake master cylinder to meet or exceed OEM standards for fit, form, and function. The cast iron construction and integrated reservoir contribute to dependable brake system performance. While specific warranty details vary, Dorman typically offers limited warranties covering defects in materials and workmanship. Consult product documentation for exact warranty terms.