National 6930 Differential Pinion Seal - Rear

National 6930 Differential Pinion Seal Overview

The National 6930 differential pinion seal is designed to provide reliable sealing performance for driveline applications. Engineered with precision, this oil seal is compatible with select Ford and Mercury models, including the Colony Park, F-100, and Thunderbird.

• Inside diameter: 1.812 inches (46.020 mm)
• Outside diameter: 4.128 inches (104.850 mm)
• Width: 0.746 inches (18.950 mm)
• Material: Leather for durability and effective sealing
• Series: 6000, Type 21 design

Technical Specifications and Design Details

The National 6930 differential pinion seal features a leather sealing element that ensures a tight fit around the shaft and housing bore, minimizing oil leakage in the differential assembly. With an inside diameter of 1.812 inches and an outside diameter of 4.128 inches, this seal fits precisely into housings with a bore diameter of approximately 4.123 inches (104.720 mm). The 0.746-inch thickness provides adequate sealing surface width to maintain oil containment under typical operating conditions. The Type 21 seal design is optimized for driveline applications, offering resistance to wear and heat generated during vehicle operation.

Compatible Vehicles and Applications

This differential pinion seal is compatible with the following vehicles:

• Ford Colony Park
• Ford F-100
• Mercury Thunderbird

It is specifically designed to replace worn or damaged seals in these models, helping to maintain proper differential function and prevent oil leaks.

Common Issues Addressed by the National 6930 Seal

• Prevents oil leaks from the differential pinion shaft
• Reduces contamination ingress into the differential housing
• Maintains proper lubrication levels within the differential
• Minimizes wear on the pinion shaft and bearings
• Helps avoid costly drivetrain repairs due to seal failure

Installation Notes and Tips

When installing the National 6930 differential pinion seal, ensure the housing bore is clean and free of debris. Use appropriate tools to press the seal evenly into place without damaging the leather sealing surface. Verify the seal is seated flush with the housing bore to prevent leaks. Lubricate the seal lip lightly with differential oil before installation to reduce initial wear. Follow vehicle-specific service manual instructions for torque specifications and installation procedures.

Quality Assurance and Warranty

National manufactures the 6930 differential pinion seal to meet industry standards for durability and performance. The leather material and precise dimensions ensure consistent sealing under normal operating conditions. While specific warranty details are not provided, National products typically adhere to quality control processes to support reliable service life in compatible Ford and Mercury vehicles.