Dorman M630891 Brake Master Cylinder

Reliable Brake Master Cylinder for Subaru Impreza and Legacy

The Dorman M630891 brake master cylinder is engineered to provide consistent hydraulic pressure for your Subaru Impreza or Legacy. Designed with an aluminum body and integrated reservoir, this master cylinder supports safe and efficient braking performance.

• Compatible with Subaru Impreza and Legacy models
• Master cylinder bore diameter: 0.813 inches
• Constructed from durable aluminum material
• Includes a single reservoir for brake fluid
• Equipped with a sensor for brake system monitoring
• Three outlet ports with M10 x 1.0 thread size
• Mounting hardware not included

Product Features and Specifications

This Dorman brake master cylinder (part number M630891) features a 0.813-inch bore diameter, crafted from aluminum to resist corrosion and provide long-lasting service. The unit includes a single reservoir to hold brake fluid, ensuring proper hydraulic pressure is maintained. It also comes with an integrated sensor to monitor brake fluid levels or pressure, enhancing safety and system diagnostics. The master cylinder has three outlets, each with M10 x 1.0 thread pitch, designed for secure and precise brake line connections. Note that mounting hardware is not included with this part.

Applications and Common Repair Uses

This brake master cylinder is specifically compatible with Subaru Impreza and Legacy vehicles, making it suitable for brake system repairs or replacements in these models. It addresses several common issues, including:

• Brake pedal feels spongy or soft due to master cylinder failure
• Brake fluid leaks from the master cylinder or reservoir
• Brake warning light triggered by sensor faults
• Reduced braking efficiency or inconsistent brake pressure
• Corrosion or wear in the original master cylinder affecting performance

Installation Notes and Tips

When installing the Dorman M630891 brake master cylinder, ensure the brake system is properly bled to remove air and maintain hydraulic integrity. Verify that the sensor connector is securely attached to maintain accurate brake fluid monitoring. Since mounting hardware is not included, reuse existing hardware or acquire compatible fasteners. Always follow vehicle-specific service manual instructions for torque specifications and safety precautions.

Quality Assurance and Warranty Information

Dorman brake master cylinders are manufactured to meet or exceed OEM standards for fit, form, and function. The aluminum construction offers corrosion resistance and durability under normal operating conditions. This part is backed by Dorman's limited warranty, providing coverage against defects in material and workmanship for a specified period. Refer to Dorman's warranty policy for detailed terms and conditions.