Dorman M390509 Brake Master Cylinder

Overview of Dorman Brake Master Cylinder M390509

The Dorman Brake Master Cylinder M390509 is designed specifically for Subaru Impreza and Legacy models, providing reliable brake hydraulics performance. This master cylinder features an aluminum construction and includes a reservoir and sensor to ensure proper brake system function.

• Compatible with Subaru Impreza and Legacy models
• Master cylinder bore diameter of 0.938 inches
• Durable aluminum master cylinder material
• Includes reservoir and sensor for accurate brake fluid management
• Four outlets with rearward outlet size M10 x 1.0 and thread pitch 1.0
• Secondary outlet thread diameter of 10 mm
• Mounting hardware not included

Detailed Product Description

The Dorman M390509 brake master cylinder is engineered to meet the hydraulic requirements of Subaru Impreza and Legacy vehicles. Constructed from aluminum, this master cylinder offers corrosion resistance and strength for long-term durability. The included reservoir allows for proper brake fluid storage, while the integrated sensor monitors fluid levels to maintain system safety. With a bore diameter of 0.938 inches and four outlets, including a rearward outlet sized M10 x 1.0, this master cylinder supports efficient brake fluid distribution. The thread pitch of 1.0 ensures secure connections with compatible brake lines. Note that mounting hardware is not included and must be sourced separately.

Common Applications and Issues Addressed

• Restores proper brake fluid pressure in Subaru Impreza and Legacy brake systems
• Replaces worn or leaking master cylinders causing brake pedal sponginess
• Resolves brake fluid leaks from damaged or corroded master cylinders
• Addresses sensor failures related to brake fluid level monitoring
• Improves brake system responsiveness and safety

Installation Notes and Tips

• Ensure compatibility with specific Subaru Impreza or Legacy model year before installation
• Bleed the brake system thoroughly after installation to remove air pockets
• Use appropriate brake fluid as specified by the vehicle manufacturer
• Verify sensor connections are secure for accurate fluid level monitoring
• Mounting hardware is not included; reuse existing hardware or obtain correct replacements

Quality Assurance and Warranty

Dorman manufactures the M390509 brake master cylinder to meet or exceed OEM specifications for fit, form, and function. The aluminum construction and integrated sensor contribute to reliable brake system performance. While specific warranty details are not provided here, Dorman products typically include a limited warranty covering defects in materials and workmanship. Consult product documentation or the manufacturer for exact warranty terms.