Dorman M390267 Brake Master Cylinder

Reliable Brake Master Cylinder for Buick, Cadillac, Oldsmobile, and Pontiac

The Dorman M390267 Brake Master Cylinder is engineered to restore proper brake hydraulics in select Buick, Cadillac, Oldsmobile, and Pontiac models. Designed with precision, this master cylinder ensures consistent brake fluid pressure for safe and effective braking performance.

• Master cylinder bore diameter: 1 inch for accurate hydraulic control
• Constructed from durable aluminum material for corrosion resistance
• Includes reservoir and sensor for integrated brake fluid management
• Features two outlets with M12 x 1.0 thread size for secure connections
• Compatible with multiple GM luxury and full-size models

Detailed Product Description

The Dorman M390267 master cylinder is crafted from aluminum, providing a lightweight yet robust component that resists corrosion and wear. Its 1-inch bore diameter is designed to deliver precise hydraulic pressure, essential for maintaining brake system integrity. This unit includes a reservoir and sensor, allowing for seamless monitoring and fluid containment within the brake system. The two outlets, both with M12 x 1.0 thread pitch, accommodate rearward and secondary outlet connections, ensuring compatibility with the brake lines of Buick 88 and 98, Cadillac DeVille and Eldorado, Oldsmobile LSS and Regency, as well as Pontiac Bonneville and Grand Prix models.

Applications and Common Issues Addressed

• Restores brake fluid pressure in vehicles experiencing spongy or unresponsive brakes
• Replaces leaking or damaged master cylinders causing brake fluid loss
• Resolves sensor-related brake warning light issues due to integrated sensor inclusion
• Addresses brake system failure symptoms in Buick, Cadillac, Oldsmobile, and Pontiac models listed
• Improves overall brake pedal feel and responsiveness

Installation Notes and Tips

Installation of the Dorman M390267 master cylinder requires proper brake fluid handling and bleeding procedures to avoid air in the brake lines. Ensure all connections use the specified M12 x 1.0 thread fittings for a secure fit. Since mounting hardware is not included, retain original fasteners or source compatible hardware. Verify sensor connections are properly seated to maintain brake system monitoring functions.

Quality Assurance and Warranty

Dorman manufactures this brake master cylinder to meet or exceed OEM specifications, using quality aluminum materials and precise machining. The inclusion of the reservoir and sensor supports system reliability. While specific warranty details are not provided here, Dorman products typically come with a limited warranty covering defects in materials and workmanship.