Dorman M104458 Brake Master Cylinder

Reliable Brake Master Cylinder for GM Classic Models

The Dorman M104458 Brake Master Cylinder is engineered to restore proper brake hydraulics in select Buick, Cadillac, Chevrolet, Oldsmobile, and Pontiac vehicles. Designed with durable aluminum construction and a dual bore design, this master cylinder ensures consistent brake fluid pressure for safe stopping performance.

• Compatible with Buick, Cadillac, Chevrolet, Oldsmobile, and Pontiac models including Bonneville, Brougham, Camaro, Caprice, Catalina, Custom Cruiser, Delta 88, DeVille, Firebird, Fleetwood, Impala, LeSabre, Parisienne, Regal, and Safari
• Dual master cylinder bore diameters: 1.125 inches and 1.578 inches for balanced braking
• Constructed from corrosion-resistant aluminum for long-lasting durability
• Includes reservoir for brake fluid storage
• Two outlet ports with rearward outlet size 1/2-20 and secondary outlet thread diameter 9/16-18
• Mounting hardware not included

Detailed Product Description

The Dorman M104458 master cylinder is a critical component in the brake hydraulics system, responsible for converting pedal force into hydraulic pressure. Its aluminum body offers resistance to corrosion and heat, which helps maintain consistent performance over time. The dual bore design with 1.125 inch and 1.578 inch diameters provides balanced pressure distribution to front and rear brakes, enhancing vehicle safety. This master cylinder comes with an integrated reservoir to hold brake fluid, simplifying installation and maintenance. It features two outlets with specific thread sizes (1/2-20 rearward outlet and 9/16-18 secondary outlet) to ensure compatibility with original brake lines on various GM vehicles.

Common Applications and Problem Resolution

• Restores brake pedal firmness and responsiveness in Buick, Cadillac, Chevrolet, Oldsmobile, and Pontiac models
• Eliminates brake fluid leaks caused by worn or damaged master cylinders
• Resolves inconsistent brake pressure and uneven braking issues
• Addresses brake warning light activation due to master cylinder failure
• Prevents brake system contamination with a sealed reservoir design

Installation Notes and Tips

• Ensure brake system is properly bled after installation to remove air pockets
• Verify outlet thread sizes (1/2-20 and 9/16-18) match vehicle brake lines before installation
• Mounting hardware is not included; reuse existing hardware or source compatible fasteners
• Inspect brake lines and hoses for wear or damage during installation
• Follow vehicle-specific service manual instructions for safe and correct installation

Quality Assurance and Warranty

Dorman manufactures the M104458 master cylinder to meet or exceed OEM specifications for fit, form, and function. The aluminum construction and precise bore diameters ensure reliable brake system performance. While mounting hardware is not included, the product is designed for direct replacement in compatible GM vehicles. Warranty coverage details should be confirmed with the point of purchase or manufacturer documentation.