Dorman M390516 Brake Master Cylinder

Reliable Brake Master Cylinder for Dodge Ram and B-Series Vans

The Dorman M390516 brake master cylinder is engineered to restore proper brake hydraulics in Dodge B1500, B2500, B3500, Ram 1500 Van, Ram 2500 Van, and Ram 3500 Van models. Designed with durable aluminum construction and a built-in reservoir, this master cylinder ensures consistent brake fluid delivery for safe and effective braking performance.

• Master cylinder bore diameter: 1.25 inches for precise hydraulic pressure
• Constructed from lightweight, corrosion-resistant aluminum
• Includes an integrated brake fluid reservoir for convenience
• 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

The Dorman M390516 brake master cylinder is designed specifically for select Dodge trucks and Ram vans, including the B1500, B2500, B3500, Ram 1500 Van, Ram 2500 Van, and Ram 3500 Van. Its 1.25-inch bore diameter provides the correct hydraulic pressure needed for these vehicles' braking systems. The aluminum material offers a balance of strength and corrosion resistance, extending the component's service life. This master cylinder comes with an integrated reservoir, eliminating the need for a separate fluid container, and features two outlets with precise thread sizes (M10 x 1.0 rearward outlet and M12 x 1.0 secondary outlet) to ensure compatibility with factory brake lines. Note that mounting hardware is not included, so existing hardware or separate purchase may be necessary.

Common Applications and Problem Resolution

• Restores brake fluid pressure in Dodge B1500, B2500, B3500, and Ram 1500/2500/3500 Vans
• Replaces master cylinders with worn or leaking seals
• Addresses spongy or unresponsive brake pedal issues
• Fixes brake fluid leaks from the master cylinder reservoir or outlets
• Improves overall brake system reliability and safety

Installation Notes and Tips

When installing the Dorman M390516 brake master cylinder, ensure the brake system is properly bled to remove air and maintain hydraulic integrity. Verify that the outlet thread sizes (M10 x 1.0 and M12 x 1.0) match your vehicle’s brake line fittings. Since mounting hardware is not included, retain original bolts or acquire compatible hardware before installation. Use appropriate brake fluid as specified by the vehicle manufacturer and follow all safety precautions during installation.

Quality Assurance and Warranty Information

Dorman manufactures the M390516 brake master cylinder to meet or exceed OEM standards for fit, form, and function. The aluminum construction and integrated reservoir are designed for durability and consistent performance. While specific warranty details may vary, Dorman typically offers a limited warranty covering defects in materials and workmanship. Consult product documentation or the supplier for exact warranty terms.