Dorman M390310 Brake Master Cylinder

Reliable Brake Master Cylinder for Jeep Wrangler

The Dorman M390310 Brake Master Cylinder is engineered to restore proper brake function in Jeep Wrangler 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 inch
• Constructed from lightweight aluminum material
• Includes integrated reservoir for brake fluid
• Two outlet ports for efficient brake line connection
• Rearward outlet size: M10 x 1.0 thread
• Secondary outlet thread diameter: M12 x 1.0
• Thread pitch: 1.0
• Package contains the master cylinder only; mounting hardware not included

Product Details and Specifications

This Dorman brake master cylinder (part number M390310) is specifically designed for Jeep Wrangler vehicles, providing a precise fit and reliable operation. The aluminum construction offers corrosion resistance and durability under demanding conditions. The 1-inch bore diameter is optimized for proper hydraulic pressure generation, while the included reservoir simplifies brake fluid management. Featuring two outlets with metric thread sizes (M10 x 1.0 and M12 x 1.0), this master cylinder supports standard brake line connections for the Jeep Wrangler's braking system.

Common Applications and Problem Resolution

• Restores brake pressure loss due to worn or damaged master cylinder
• Eliminates brake fluid leaks from the master cylinder reservoir
• Resolves spongy or unresponsive brake pedal feel
• Addresses brake system failure caused by internal cylinder wear
• Replaces corroded or cracked master cylinder housing

Installation Notes and Tips

When installing the Dorman M390310 master cylinder on a Jeep Wrangler, ensure the brake system is properly bled to remove air and maintain hydraulic integrity. Use compatible brake fluid as specified by the vehicle manufacturer. Since mounting hardware is not included, retain or source the necessary bolts and fittings for secure installation. Verify thread sizes (M10 x 1.0 and M12 x 1.0) to ensure proper brake line connection.

Quality Assurance and Warranty

Dorman manufactures this brake master cylinder to meet or exceed OEM standards for fit and function. The aluminum material provides corrosion resistance for extended service life. While specific warranty details are not provided, Dorman products typically come with a limited warranty covering defects in materials and workmanship. Refer to Dorman's official documentation for exact warranty terms.