Dorman M71277 Brake Master Cylinder

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

The Dorman M71277 brake master cylinder is engineered to restore proper brake hydraulics in select Buick, Jeep, Oldsmobile, and Pontiac vehicles. Designed with durable cast iron and a built-in reservoir, this master cylinder ensures consistent brake fluid delivery for safe and effective braking performance.

• Master cylinder bore diameter: 1 inch
• Constructed from durable cast iron material
• Includes reservoir for brake fluid
• Two outlet ports with rearward outlet size 9/16-18
• Secondary outlet thread diameter of 0.5 inches
• Package contains the master cylinder only; mounting hardware not included

Durable Construction and Precise Specifications

The Dorman M71277 master cylinder features a 1-inch bore diameter made from cast iron, providing strength and resistance to wear. Its integrated reservoir simplifies installation and maintenance by holding the brake fluid securely. The unit includes two outlets, with a rearward outlet thread size of 9/16-18 and a secondary outlet thread diameter of 0.5 inches, ensuring compatibility with the brake lines on your vehicle. This master cylinder is designed without a sensor and does not include mounting hardware, so be sure to prepare accordingly during installation.

Compatible Vehicles and Applications

This brake master cylinder is compatible with a range of classic and utility vehicles, including Buick models like the Cutlass, Cutlass Supreme, Delta 88, LeMans, Skylark, and Tempest. It also fits Jeep models such as the Cherokee, CJ5, CJ7, Wagoneer, and trucks like the J10 and J20. Additionally, it suits Oldsmobile and Pontiac vehicles including the Firebird, Grand Prix, and GTO. The Dorman M71277 is ideal for restoring brake hydraulics on these specific makes and models.

Common Brake System Issues Addressed

• Brake pedal sinking or sponginess due to master cylinder wear
• Brake fluid leaks from a damaged or corroded master cylinder
• Inconsistent brake pressure affecting stopping performance
• Brake warning light activation related to hydraulic failure
• Replacement of a faulty or worn-out master cylinder in classic Buick, Jeep, Oldsmobile, or Pontiac vehicles

Installation Notes and Tips

When installing the Dorman M71277 master cylinder, ensure the brake system is properly bled to remove air and maintain hydraulic integrity. Since mounting hardware is not included, retain or source the correct bolts and fittings for your specific vehicle. Verify outlet thread sizes to match existing brake lines, especially the rearward outlet size of 9/16-18 and secondary outlet thread diameter of 0.5 inches. Proper torque specifications should be followed to avoid leaks or damage.

Quality Assurance and Warranty

Dorman manufactures the M71277 brake master cylinder to meet or exceed OEM standards for fit, form, and function. The cast iron construction provides durability and long service life. While mounting hardware and sensors are not included, the product is backed by Dorman's quality control processes. Please refer to Dorman's warranty policy for specific coverage details.