Dorman M390071 Brake Master Cylinder

Overview of Dorman Brake Master Cylinder M390071

The Dorman Brake Master Cylinder M390071 is designed specifically for Jeep Cherokee, Grand Cherokee, and Wrangler models. This cast iron master cylinder includes a reservoir and features precise outlet threading to ensure reliable brake hydraulics performance.

• Master cylinder bore diameter: 1 inch
• Constructed from durable cast iron material
• Includes reservoir for brake fluid
• Two outlets 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
• Mounting hardware not included
• Package contains the master cylinder only

Detailed Product Description

The Dorman M390071 brake master cylinder is engineered to meet the hydraulic braking needs of Jeep Cherokee, Grand Cherokee, and Wrangler vehicles. Its 1-inch bore diameter provides consistent hydraulic pressure, while the cast iron construction offers strength and durability under demanding conditions. The included reservoir simplifies installation and maintenance by providing a ready-to-use brake fluid container. With two outlets featuring specific thread sizes (M10 x 1.0 rearward outlet and M12 x 1.0 secondary outlet), this master cylinder ensures compatibility with the brake lines of the specified Jeep models. The 1.0 thread pitch further guarantees a secure and leak-free connection.

Common Applications and Issues Addressed

• Restores proper brake fluid pressure for Jeep Cherokee, Grand Cherokee, and Wrangler
• Replaces worn or leaking master cylinders causing brake pedal sponginess
• Solves brake fluid reservoir leaks or contamination issues
• Addresses brake failure symptoms related to master cylinder wear
• Improves brake system reliability and safety

Installation Notes and Tips

• Ensure brake system is properly bled after installation to remove air
• Verify thread sizes (M10 x 1.0 and M12 x 1.0) match vehicle brake lines before installation
• Mounting hardware is not included; reuse existing hardware or source separately
• Inspect brake lines and fittings for wear or damage during replacement
• Follow vehicle manufacturer torque specifications for secure installation

Quality Assurance and Warranty

Dorman manufactures the M390071 brake master cylinder to meet or exceed OEM standards for Jeep Cherokee, Grand Cherokee, and Wrangler models. The cast iron construction and precise machining ensure durability and reliable performance. While mounting hardware is not included, the product is backed by Dorman's quality control processes. Please refer to Dorman's official warranty policy for specific coverage details.