Dorman M390400 Brake Master Cylinder

Reliable Brake Master Cylinder for Ford Explorer and Ranger

The Dorman M390400 Brake Master Cylinder is engineered to restore proper brake hydraulics in select Ford vehicles. Designed specifically for Ford Explorer, Explorer Sport, Explorer Sport Trac, and Ranger models, this master cylinder ensures consistent brake fluid pressure and reliable stopping power.

• Master cylinder bore diameter: 1.063 inches for precise hydraulic control
• Constructed from durable aluminum material for corrosion resistance
• Includes reservoir and sensor for integrated brake fluid management
• Features three outlets with a secondary outlet thread diameter of 10 mm
• Rearward outlet size: M18 x 1.5 with a thread pitch of 1.0 for secure connections
• Package contains the master cylinder unit; mounting hardware not included

Product Details and Specifications

The Dorman M390400 brake master cylinder is crafted from aluminum, providing a lightweight yet robust component that resists corrosion and wear. Its 1.063-inch bore diameter is calibrated to deliver consistent hydraulic pressure, essential for the braking systems in Ford Explorer and Ranger vehicles. The included reservoir and sensor facilitate accurate monitoring and fluid management, contributing to overall brake system reliability. With three outlets, including a secondary outlet with a 10 mm thread diameter and a rearward outlet sized M18 x 1.5, this master cylinder supports proper brake line connections and fluid distribution. The thread pitch of 1.0 ensures compatibility with OEM brake fittings.

Compatible Vehicles and Applications

This brake master cylinder is compatible with the following Ford models:

• Ford Explorer
• Ford Explorer Sport
• Ford Explorer Sport Trac
• Ford Ranger

It is designed to replace worn or failing master cylinders in these vehicles, restoring brake system performance and safety.

Common Issues Addressed by This Master Cylinder

• Spongy or unresponsive brake pedal
• Brake fluid leaks from the master cylinder or reservoir
• Brake warning light activation due to sensor faults
• Reduced hydraulic pressure causing poor braking performance
• Contaminated or deteriorated brake fluid reservoir

Installation Notes and Tips

Installation of the Dorman M390400 master cylinder requires proper brake system bleeding to remove air and ensure optimal hydraulic function. Note that mounting hardware is not included, so existing hardware should be inspected and replaced if necessary. Verify thread sizes and pitch compatibility with your vehicle’s brake lines before installation. Sensor connections should be carefully reattached to maintain brake system monitoring.

Quality Assurance and Warranty

Dorman manufactures this brake master cylinder to meet or exceed OEM specifications for fit, form, and function. The aluminum construction and integrated sensor contribute to long-term durability. While specific warranty details are not provided here, Dorman typically offers limited warranties on their brake hydraulics products to cover defects in materials and workmanship.