Dorman M80903 Brake Master Cylinder

Reliable Brake Master Cylinder for Ford, Lincoln, and Mercury Vehicles

The Dorman M80903 brake master cylinder is engineered to restore proper brake hydraulics in select Ford, Lincoln, and Mercury models. Designed with durable cast iron and a built-in reservoir, this master cylinder ensures consistent brake fluid delivery for safe stopping performance.

• Master cylinder bore diameter: 1 inch for precise hydraulic pressure
• Constructed from cast iron for long-lasting durability
• Includes reservoir for brake fluid containment
• Two outlets with rearward outlet size of 9/16-18 and secondary outlet thread diameter of 0.5 inches
• Compatible with Ford Colony Park, Lincoln Continental, Mercury Cougar, Grand Marquis, LTD, Marquis, Montego, and Thunderbird

Durable Cast Iron Construction and Precise Hydraulic Design

The Dorman M80903 brake master cylinder features a robust cast iron body that withstands the rigors of daily driving and brake system pressure. Its 1-inch bore diameter is calibrated to provide accurate hydraulic force to the brake calipers or wheel cylinders. The integrated reservoir simplifies brake fluid management, while the two outlet ports with specific thread sizes ensure proper connection to the brake lines. This master cylinder is designed specifically for rearward outlet configurations with a 9/16-18 thread size, making it a direct replacement for compatible Ford, Lincoln, and Mercury vehicles.

Compatible Vehicles and Common Applications

This brake master cylinder is compatible with a range of Ford, Lincoln, and Mercury models, including:

• Ford Colony Park
• Lincoln Continental
• Mercury Cougar
• Grand Marquis
• LTD
• Marquis
• Montego
• Thunderbird

It is designed to address issues such as:

• Spongy or unresponsive brake pedal
• Brake fluid leaks from the master cylinder
• Brake warning light activation due to hydraulic failure
• Reduced braking efficiency or uneven brake pressure
• Contaminated or damaged brake fluid reservoir

Installation Notes and Tips

When installing the Dorman M80903 brake master cylinder, ensure the brake system is properly bled to remove air pockets and maintain hydraulic integrity. This part does not include mounting hardware, so retain original fasteners or acquire appropriate replacements. Verify the rearward outlet thread size (9/16-18) matches your vehicle’s brake line fittings for a secure connection. Proper torque specifications should be followed to avoid leaks or damage.

Quality Assurance and Warranty Information

Dorman manufactures this brake master cylinder to meet or exceed OEM standards for fit, form, and function. The cast iron construction and integrated reservoir are tested for durability and performance under typical operating conditions. While specific warranty details are not provided here, Dorman products generally come with a limited warranty against defects in materials and workmanship. Consult product documentation or the manufacturer for exact warranty terms.