Dorman M390139 Brake Master Cylinder

Overview of Dorman Brake Master Cylinder M390139

The Dorman Brake Master Cylinder M390139 is designed specifically for Nissan Altima and Infiniti G20 models. This brake hydraulics component features an aluminum construction and includes a reservoir and sensor to ensure reliable brake system performance.

• Compatible with Nissan Altima and Infiniti G20
• Master cylinder bore diameter: 0.938 inches
• Constructed from durable aluminum material
• Includes reservoir and sensor for integrated functionality
• Four outlets with secondary outlet thread diameter of 10 mm
• Rearward outlet size: M10 x 1.0 with 1.0 thread pitch
• Mounting hardware not included

Detailed Product Description

The Dorman M390139 brake master cylinder is engineered to meet the specifications required for proper brake hydraulics operation in Nissan Altima and Infiniti G20 vehicles. Its aluminum body offers corrosion resistance and strength, while the 0.938-inch bore diameter ensures consistent hydraulic pressure. The included reservoir allows for fluid storage, and the integrated sensor provides feedback for brake system monitoring. With four outlets and precise thread dimensions, this master cylinder supports efficient brake fluid distribution to the vehicle’s braking system.

Common Applications and Problem Resolution

This brake master cylinder is used to replace worn or failing units in compatible Nissan and Infiniti models. It addresses several brake system issues, including:

• Brake pedal sinking or sponginess
• Brake fluid leaks from the master cylinder
• Inconsistent brake pressure or poor braking response
• Warning light activation due to sensor failure
• Reservoir damage or fluid contamination

Installation Notes and Tips

Installation of the Dorman M390139 master cylinder requires proper brake system bleeding to remove air and ensure optimal performance. Note that mounting hardware is not included, so existing hardware should be inspected and replaced if necessary. Verify thread pitch and outlet sizes to ensure compatibility with the vehicle’s brake lines. Sensor connections should be securely attached to maintain accurate brake system monitoring.

Quality Assurance and Warranty

Dorman manufactures this 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. While specific warranty details should be confirmed at the time of purchase, Dorman typically offers limited warranties covering defects in materials and workmanship.