Dorman M40000 Brake Master Cylinder

Reliable Brake Master Cylinder for Classic GM Vehicles

The Dorman M40000 brake master cylinder is engineered to restore proper brake hydraulics in select Buick, Chevrolet, Jeep, Oldsmobile, and Pontiac models. Designed with a durable cast iron body 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 storage
• Single outlet design with 7/16-24 rearward outlet size
• Mounting hardware not included
• Compatible with classic models such as Chevrolet Bel Air, Buick LeMans, Pontiac GTO, and Jeep Wagoneer

Durable Construction and Precise Fitment

The Dorman M40000 brake master cylinder features a cast iron construction that withstands the rigors of brake system pressure and heat. Its 1-inch bore diameter is designed to provide consistent hydraulic force, ensuring reliable brake pedal feel and stopping power. The integrated reservoir simplifies installation and maintenance by housing the brake fluid securely. This master cylinder is engineered specifically for rearward outlet brake systems with a 7/16-24 outlet size, making it suitable for a range of classic GM and Jeep vehicles.

Compatible Vehicles and Applications

This brake master cylinder is compatible with a variety of classic American vehicles, including:

• Buick models such as LeMans and Skylark
• Chevrolet models including Bel Air, Caprice, Impala, and El Camino
• Jeep Wagoneer
• Oldsmobile Cutlass, Delta 88, and 98
• Pontiac GTO, Grand Prix, Catalina, and Tempest

Use the Dorman M40000 to replace worn or leaking master cylinders in these vehicles to restore proper brake hydraulics.

Common Issues Addressed by This Master Cylinder

• Brake pedal sinking or sponginess due to internal leaks
• Brake fluid reservoir leaks or cracks
• Inconsistent brake pressure causing uneven braking
• Brake system failure from worn or damaged master cylinder bore
• Hydraulic fluid contamination or loss

Installation Notes and Tips

Installation of the Dorman M40000 master cylinder requires careful attention to brake line connections and bleeding procedures. Note that mounting hardware is not included, so original or aftermarket hardware will be needed. Ensure the brake fluid reservoir is filled with the correct fluid type and bleed the brake system thoroughly to remove air pockets. Proper torque specifications should be followed to avoid leaks or damage.

Quality Assurance and Warranty

Dorman manufactures this brake master cylinder to meet or exceed OEM specifications for fit, form, and function. The cast iron construction and integrated reservoir are tested for durability and performance. 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.