National 4990 Wheel Seal - Front Inner

National 4990 Wheel Seal Overview

The National 4990 wheel seal is engineered for reliable driveline protection in select Ford, Kia, Mazda, and Mercury vehicles. Designed to maintain optimal sealing performance, this oil seal helps prevent leaks and contamination in wheel hubs for models like the Ford Aspire, Mazda 323, and Kia Rio.

• Inside diameter: 2.047 inches (52.000 mm)
• Outside diameter: 2.688 inches (68.280 mm)
• Housing bore: 2.677 inches (68.000 mm)
• Overall width with side lip: 0.520 inches (13.200 mm)
• Width: 0.276 inches (7.000 mm)
• Material: durable nitrile rubber
• Redicoat coating for enhanced corrosion resistance
• Series 4000, Type 281 oil seal

Technical Details and Material Specifications

This National 4990 wheel seal is constructed from nitrile, a synthetic rubber known for its resistance to oil, heat, and wear. The seal features a Redicoat finish, which provides additional protection against corrosion, extending the service life of the component. With precise dimensions including a 2.047-inch inside diameter and a 2.688-inch outside diameter, it fits securely within the housing bore of 2.677 inches, ensuring a tight seal around the shaft.

Compatible Vehicles and Applications

The National 4990 wheel seal is compatible with various models from Ford, Kia, Mazda, and Mercury. Specifically, it fits Ford Aspire and Capri, Kia Rio, Mazda 323 and Tracer, and Mercury Festiva models. This part is designed to maintain the integrity of the wheel hub assembly by preventing oil leaks and keeping contaminants out.

Common Issues Addressed by the National 4990 Wheel Seal

• Prevents oil leakage from wheel hubs
• Protects bearings from dirt and moisture contamination
• Reduces premature wear of driveline components
• Maintains proper lubrication within the axle assembly
• Helps avoid costly repairs due to seal failure

Installation Notes and Tips

When installing the National 4990 wheel seal, ensure the housing bore and shaft are clean and free of debris. Use appropriate tools to press the seal evenly into place without damaging the sealing lip. Verify the seal orientation matches the original part, with the Redicoat side facing outward for corrosion protection. Proper installation will help maintain the seal’s effectiveness and extend the life of the driveline components.

Quality Assurance and Warranty Information

National wheel seals, including part number 4990, are manufactured to meet industry standards for durability and performance. The use of nitrile material and Redicoat finish ensures resistance to oil and corrosion. While specific warranty details may vary, National typically offers coverage against manufacturing defects to provide confidence in the product’s reliability.