National 340151 Steering Gear Sector Shaft Seal

Steering Gear Sector Shaft Seal for Ford Applications

The National 340151 steering gear sector shaft seal is built for manual steering gear service where a precise seal is needed at the sector shaft. It uses nitrile sealing material and is sized for a 1.125-inch shaft, making it a direct-match option for many Ford and Mercury steering gear applications.

National has supplied sealing solutions for decades, and this oil seal is part of the 340000 series. For restorations and repairs on vehicles such as the Ford F-100, Ford Bronco, and Ford Mustang, the 340151 helps address leakage at the steering gear sector shaft.

Key Features

• Part number: National 340151
• Steering gear sector shaft seal / oil seal
• Nitrile sealing material for steering gear service
• Inside diameter: 1.125 in. (28.580 mm)
• Outside diameter: 1.569 in. (39.850 mm)
• Thickness/width: 0.250 in. (6.350 mm)
• Housing bore: 1.561 in. (39.650 mm)
• Series: 340000
• Type 34 seal design

Detailed Description

The National 340151 is a steering gear sector shaft seal designed around common Ford Design steering gear dimensions. Its nitrile construction is suited for sealing service in manual steering systems, where the sector shaft passes through the steering gear housing and requires a tight oil seal to retain lubricant and reduce seepage. This part number is frequently searched for Ford F-250, Ford Thunderbird, and Mercury Cougar steering gear repairs, especially on older vehicles with manual steering.

This part cross-references SKF 18757 and Gates 51375 for the same application. National 340151 is also listed across a wide range of interchange references for classic Ford, Mercury, and select Cadillac steering gear service.

What It Helps Address

• Steering gear oil leakage at the sector shaft
• Wet or contaminated steering gear housings
• Wear-related seepage in manual steering boxes
• Seal replacement during steering gear rebuilds
• Restoration work on older Ford and Mercury steering systems

Installation Notes and Tips

Verify shaft diameter, housing bore, and steering gear design before installation. This seal is specified for a 1.125-inch shaft and 1.561-inch housing bore, so matching the steering box dimensions is critical. Clean the housing thoroughly, inspect the sector shaft for scoring or wear, and confirm the vehicle uses the correct Ford Design steering gear before assembly. Fitment includes 1975-1982 Ford E-100 Econoline, E-150 Econoline, E-250 Econoline, E-350 Econoline, F-100, F-150, F-250, and F-350 applications with Ford Design, plus manual-steering applications such as 1966-1974 Ford Bronco, 1965-1973 Ford LTD, 1960-1973 Ford Thunderbird, 1967-1973 Mercury Cougar, and 1968-1974 Mercury Montego.

Quality Assurance

National is known for sealing products backed by long-term industry experience and ongoing design support for modern and legacy vehicle service. The 340151 is engineered as a precision steering gear seal for consistent fitment in supported Ford and Mercury applications.