National 308 Wheel Bearing - Rear or Rear Outer

National 308 Wheel Bearing Overview

The National 308 wheel bearing is a single row radial ball bearing built for rear driveline and axle applications that call for a 40 mm bore and 90 mm outside diameter. It is manufactured to meet or exceed OE quality standards and is designed for consistent operation and extended bearing life in demanding service.

Compatible With select Ford F-250, Ford F-250 HD, Ford F-350, Nissan 720, and Mercedes-Benz 300-series rear applications, this bearing is a direct-fit service part for vehicles that use the specified dimensions and transfer case configurations.

• Part number: 308
• Single row radial ball bearing design
• 40.000 mm bore / 1.575 in bore
• 90.000 mm outside diameter / 3.543 in outside diameter
• 23.000 mm width / 0.906 in width
• Type A-1, Series 300
• Rear position applications

Fitment and Application Details

Fits 1996-1997 Ford F-250, Rear, with Borg-Warner 4407 Transfer Case; with Part Time 4WD; 2 Speed. Fits 1997 Ford F-250 HD, Rear, with Borg-Warner 4407 Transfer Case; with Part Time 4WD; 2 Speed. Fits 1994-1997 Ford F-350, Rear, with Borg-Warner 4407 Transfer Case; with Part Time 4WD; 2 Speed.

Fits 1980-1986 Nissan 720, Rear, with Fuji Univance T100L Transfer Case; with Part Time 4WD; 2 Speed. Fits 1963-1967 Mercedes-Benz 300SEL, Rear. Fits 1960-1966 Mercedes-Benz 300SE, Rear. Fits 1954-1963 Mercedes-Benz 300SL, Rear. Fits 1958-1962 Mercedes-Benz 300D, Rear.

• Rear wheel bearing service for Ford F-250 and F-350 4WD driveline setups
• Rear bearing replacement for Nissan 720 part-time 4WD applications
• Rear axle bearing service on Mercedes-Benz 300SL, 300SE, 300SEL, and 300D models
• Noise, roughness, or looseness at the wheel end
• Wear-related bearing replacement during driveline repair

Installation Notes and Tips

Verify bore, outside diameter, width, and race dimensions before installation to confirm the correct match for the hub or axle assembly. This bearing is specified for rear applications, so confirm the vehicle’s transfer case and 4WD configuration where listed. Clean the bearing seat and inspect related seals, races, and mating surfaces during service to help ensure proper fit and smooth operation.

Quality Assurance

National manufactures this bearing to exacting standards with OE-quality expectations in mind. The 308 is built for dependable performance in wheel-bearing service and is backed by the brand’s focus on dimensional accuracy and bearing life.

This part cross-references SKF (e.g., 6308-J, 550247) for the same application.