Dorman M39767 Brake Master Cylinder

Reliable Brake Master Cylinder for Chevrolet and GMC Trucks

The Dorman M39767 brake master cylinder is engineered to restore proper brake hydraulics in Chevrolet C3500 and GMC K3500 trucks. Designed with durable aluminum construction and a built-in reservoir, this master cylinder ensures consistent brake fluid delivery for safe stopping performance.

• Master cylinder bore diameter: 1.25 inches for precise hydraulic pressure
• Constructed from lightweight, corrosion-resistant aluminum
• Includes an integrated reservoir for brake fluid
• Two outlet ports with rearward outlet size 1/2-20 and secondary outlet thread diameter 9/16-18
• Compatible with Chevrolet C3500 and GMC K3500 models
• Part number M39767 for accurate replacement

Product Details and Specifications

The Dorman M39767 brake master cylinder features a 1.25-inch bore diameter, which is critical for maintaining the correct hydraulic pressure in the brake system. Its aluminum construction offers durability and resistance to corrosion, extending the service life of the component. The included reservoir simplifies installation and maintenance by providing a ready-to-use brake fluid container. This master cylinder has two outlets, with a rearward outlet size of 1/2-20 and a secondary outlet thread diameter of 9/16-18, ensuring compatibility with the brake lines on Chevrolet C3500 and GMC K3500 trucks.

Common Applications and Problem Resolution

• Restores brake fluid pressure in Chevrolet C3500 and GMC K3500 brake systems
• Replaces worn or leaking master cylinders causing brake pedal sponginess
• Addresses brake fluid leaks from damaged or corroded master cylinders
• Improves brake response and pedal feel in heavy-duty trucks
• Prevents brake system failure due to master cylinder malfunction

Installation Notes and Tips

When installing the Dorman M39767 brake master cylinder, ensure the brake fluid reservoir is properly filled and free of contaminants. Bleed the brake system thoroughly to remove air pockets and verify that all outlet connections match the specified thread sizes (1/2-20 rearward outlet and 9/16-18 secondary outlet). This part does not include mounting hardware, so retain original fasteners or source compatible replacements. Proper torque specifications should be followed to avoid leaks or damage.

Quality Assurance and Warranty

Dorman manufactures the M39767 brake master cylinder to meet or exceed OEM standards for fit, form, and function. The aluminum construction and integrated reservoir contribute to long-term reliability. While specific warranty details are not provided here, Dorman typically offers limited warranties on their brake hydraulics components to ensure customer confidence and product durability.