Dorman M630940 Brake Master Cylinder

Reliable Brake Master Cylinder for Hyundai and Kia Vehicles

The Dorman M630940 brake master cylinder is engineered to restore proper brake hydraulics in select Hyundai and Kia models. Designed with durable cast iron and equipped with a removable reservoir, this master cylinder ensures consistent braking performance for your Optima or Sonata.

• Master cylinder bore diameter: 0.9375 inches for precise hydraulic pressure
• Constructed from cast iron for long-lasting durability
• Includes a removable reservoir for easy maintenance
• Equipped with a sensor to monitor brake fluid levels
• Two outlets with M12 x 1.0 thread size for secure connections

Durable Construction and Functional Design

This Dorman brake master cylinder (part number M630940) features a cast iron body that withstands the rigors of daily driving and brake system pressure. The 0.9375-inch bore diameter is calibrated to deliver accurate hydraulic force to the brake calipers. The included removable reservoir simplifies fluid checks and refills, while the integrated sensor provides real-time monitoring of brake fluid levels to help maintain safety. With two outlets threaded M12 x 1.0, this master cylinder ensures compatibility with the brake lines on Hyundai Optima and Kia Sonata models.

Compatible Hyundai and Kia Models

This brake master cylinder is specifically designed for use in Hyundai Optima and Kia Sonata vehicles, providing a direct replacement for the original part. Using the Dorman M630940 ensures proper fitment and reliable brake system operation in these models.

Common Brake System Issues Addressed

• Brake pedal feels spongy or sinks to the floor
• Brake fluid leaks from the master cylinder or reservoir
• Warning light triggered by low brake fluid sensor
• Reduced braking efficiency or inconsistent brake pressure
• Corroded or damaged master cylinder body affecting performance

Installation Notes and Tips

Installation of the Dorman M630940 brake master cylinder requires proper brake system bleeding to remove air and ensure optimal hydraulic pressure. The removable reservoir allows for easier fluid handling during installation. Verify that the sensor connector is securely attached to maintain brake fluid level monitoring. This part does not include mounting hardware, so retain original fasteners or source replacements as needed.

Quality Assurance and Warranty

Dorman brake master cylinders are manufactured to meet or exceed OEM specifications, providing reliable performance and durability. The M630940 part is backed by Dorman's quality standards, ensuring a dependable replacement for your Hyundai Optima or Kia Sonata brake system. Please refer to Dorman's warranty policy for specific coverage details.