National 51098 Wheel Seal - Rear, Rear Inner or Rear Outer

National 51098 Wheel Seal for Rear Axles

National 51098 is a wheel seal built for rear axle sealing applications on a wide range of Ford, Lincoln, Mercury, and select Buick vehicles. It uses nitrile sealing material and a Redicoat finish to support a secure seal at the housing bore and shaft interface.

With a 1.500 inch inside diameter, 2.506 inch outside diameter, and 0.437 inch width, this seal is sized for specific driveline and axle applications where accurate dimensions matter. National 51098 is a direct-fit option for rear axle service on vehicles such as the Ford F-100, Ford Bronco, and Lincoln Continental.

Key Features

• Part number: 51098
• Wheel seal / oil seal for driveline and axle service
• Nitrile sealing material for dependable sealing performance
• Redicoat finish
• Inside diameter: 1.500 in. (38.100 mm)
• Outside diameter: 2.506 in. (63.650 mm)
• Width: 0.437 in. (11.100 mm)
• Housing bore: 2.502 in. (63.550 mm)
• National 50000 series

Detailed Description

National has supplied sealing solutions for more than 75 years, and the 51098 reflects that focus on dimensional accuracy and application-specific fitment. This seal is engineered with nitrile material and a 48-type design to help maintain a reliable seal in rear axle and output shaft locations where oil control is critical. It is listed for rear and rear inner positions across multiple classic truck and passenger car applications, including Ford F-100, Ford E-150 Econoline, Mercury Cougar, and Lincoln Versailles.

This part cross-references SKF 15142 for the same application.

What It Helps Address

• Gear oil seepage at the wheel end or axle seal area
• Contamination entering the axle housing
• Seal wear from age, heat, and mileage
• Leak-related fluid loss in rear axle service
• Noise or driveline issues caused by inadequate sealing

Installation Notes and Tips

Verify shaft, housing bore, and width dimensions before installation. Confirm the exact position and axle configuration, since fitment varies by ring gear size, axle rating, and transmission/output shaft application. For example, this seal fits 1964-1979 Ford F-100, rear, with 9 in. ring gear and 3,300 lb axle; 1966-1977 Ford Bronco, rear, with 9 in. ring gear and 3,300 lb axle; and 1977-1979 Lincoln Versailles, rear inner, manual transmission output shaft seal for vehicles with 31 splines.

Clean the sealing surface thoroughly and inspect the shaft for grooves or wear before assembly. Accurate installation is important for rear axle service on Ford, Lincoln, and Mercury applications.

Quality Assurance

National is recognized for premium sealing solutions and ongoing engineering support for modern and legacy vehicle applications. The 51098 is part of the National 50000 series and is built to meet the dimensional requirements listed for the specified fitments.