Dorman M390398 Brake Master Cylinder

Reliable Brake Master Cylinder for Ford, Lincoln, Mazda, and Mercury

The Dorman M390398 Brake Master Cylinder is engineered to restore proper brake hydraulics in select Ford, Lincoln, Mazda, and Mercury vehicles. Designed with precision, this master cylinder includes a reservoir and sensor to ensure optimal brake system performance.

• Master cylinder bore diameter: 1.063 inches for accurate hydraulic pressure
• Constructed from durable aluminum material for corrosion resistance
• Includes reservoir and sensor for integrated brake fluid management
• Four outlets with rearward outlet sizes M10 x 1.0 and M12 x 1.0
• Secondary outlet thread diameter: M10 x 1.0 and 3/8-24
• Compatible with Ford Aviator, Escape, Explorer, Ranger; Lincoln Aviator, Mountaineer; Mazda B2300, B2500, B3000, B4000; Mercury Mountaineer

Product Features and Specifications

The Dorman M390398 brake master cylinder is crafted from aluminum, providing a lightweight yet robust component that resists corrosion and wear. Its 1.063-inch bore diameter ensures consistent hydraulic pressure for reliable braking response. This unit comes complete with an integrated reservoir and sensor, facilitating accurate fluid level monitoring and system feedback. Featuring four outlets, including rearward outlet sizes of M10 x 1.0 and M12 x 1.0, and secondary outlet threads of M10 x 1.0 and 3/8-24, it supports complex brake line configurations found in various Ford, Lincoln, Mazda, and Mercury models.

Applications and Common Brake System Issues

• Restores brake pressure loss due to worn or damaged master cylinder
• Eliminates brake fluid leaks from faulty seals or reservoir
• Resolves brake pedal sinking or sponginess caused by internal cylinder wear
• Addresses sensor-related brake warning light issues
• Improves overall brake system responsiveness and safety

Installation Notes and Tips

Installation of the Dorman M390398 master cylinder requires careful attention to brake fluid handling and bleeding procedures. Since mounting hardware is not included, ensure you have the correct bolts and fittings for your specific vehicle model. Properly connect all four outlets according to the vehicle’s brake line layout, and verify sensor connections for accurate brake system monitoring. After installation, thoroughly bleed the brake system to remove air and confirm firm pedal feel before driving.

Quality Assurance and Warranty Information

Dorman manufactures the M390398 brake master cylinder to meet or exceed OEM standards for fit, form, and function. The aluminum construction and integrated sensor contribute to long-term durability and reliable operation. While specific warranty details may vary, Dorman typically offers a limited warranty covering defects in material and workmanship to provide confidence in your replacement part.