Dorman M390426 Brake Master Cylinder

Reliable Brake Master Cylinder for Dodge Ram Trucks

The Dorman M390426 Brake Master Cylinder is engineered to restore proper brake function in Dodge Ram 1500, Ram 2500, and Ram 3500 models. Designed with durable aluminum construction and a built-in reservoir, this master cylinder ensures consistent hydraulic pressure for safe braking performance.

• Master cylinder bore diameter: 1.25 inches for precise hydraulic control
• Constructed from lightweight, corrosion-resistant aluminum
• Includes an integrated reservoir for brake fluid
• Two outlet ports with rearward outlet size M10 x 1.0 and secondary outlet thread diameter M12 x 1.0
• Thread pitch of 1.0 for secure fitting
• Package contains the master cylinder only; mounting hardware not included

Product Details and Specifications

This Dorman brake master cylinder (part number M390426) is specifically designed for Dodge Ram 1500, 2500, and 3500 trucks, providing a direct replacement for the original equipment. The aluminum material offers durability and resistance to corrosion, which is critical for brake hydraulics exposed to varying temperatures and moisture. The 1.25-inch bore diameter ensures proper hydraulic pressure is maintained, contributing to consistent brake pedal feel and stopping power. The integrated reservoir simplifies installation and maintenance by housing the brake fluid securely. With two outlets featuring precise thread sizes (M10 x 1.0 rearward outlet and M12 x 1.0 secondary outlet), this master cylinder fits the brake lines of compatible Dodge Ram models without modification.

Common Applications and Problem Resolution

• Restores brake pressure loss due to worn or leaking master cylinder
• Eliminates spongy or unresponsive brake pedal issues
• Replaces master cylinders with damaged or corroded reservoirs
• Addresses brake fluid leaks from faulty seals or ports
• Improves overall brake system reliability in Dodge Ram 1500, 2500, and 3500 trucks

Installation Notes and Tips

Installation of the Dorman M390426 master cylinder requires basic brake system knowledge and tools. Since mounting hardware is not included, retain original mounting bolts or acquire compatible replacements. Properly bench bleed the master cylinder before installation to remove air and ensure optimal brake performance. Verify thread sizes (M10 x 1.0 and M12 x 1.0) match your vehicle’s brake lines to avoid leaks. After installation, bleed the brake system thoroughly to eliminate air pockets and confirm firm brake pedal feel.

Quality Assurance and Warranty Information

Dorman manufactures this brake master cylinder to meet or exceed OEM standards for fit, form, and function. The aluminum construction and integrated reservoir are designed for long-term durability under normal operating conditions. While specific warranty details are not provided here, Dorman typically offers limited warranties on their brake hydraulic components. Consult product documentation or the manufacturer for exact warranty terms.