OTC 6698 Wheel Knuckle Vacuum Oil Seal Installer for Ford 2006 To Current F-450/550 Ford Axle Shaft Seal Installer For use on 2005 and newer Ford F-450 and F-550 4X4s with vacuum-actuated front axles Correctly installs the seal onto the axle shaft and into the wheel knuckle Seal prevents front hub vacuum leaks that would cause the vacuum actuated front axle to not engage Rugged construction ensures reliable long-term service