Ford Super Duty Front Axle Shaft Seal Installer 6697

Ford Super Duty trucks with vacuum-actuated front hub locks depend on a seal pressed into the steering knuckle around the axle shaft. When that seal is cocked, cut, or pushed in unevenly, the hub loses vacuum, the locks never fully engage, and you get the classic complaint: the 4WD light comes on but the front wheels are not driving. A leaking knuckle seal also lets gear oil and road water past, which rusts the hub bearing and shaft.

This is a 6697-pattern installer: a stepped steel driver with a flanged face sized to the knuckle bore and a pilot sleeve that rides over the axle shaft. The pilot keeps the driver centered on the shaft, and the flange stops it at the correct depth, so the seal goes in square and to depth in one pass instead of being tapped around its edge with a punch.

On the truck: pull the hub and bearing assembly, remove the old seal from the knuckle, clean the bore, and lightly lube the new seal lip. Set the seal on the driver, slide the pilot over the axle shaft, and drive it in with a hammer until the flange bottoms against the knuckle. Reinstall the hub, then check the hub lock vacuum circuit with a hand pump before you call it done. Do both sides at the same time if one has failed; the other is usually close behind.

Fits Ford F-250, F-350, F-450, and F-550 Super Duty 4x4 front axles with vacuum hub locks, listed for 1998-2004 and for 2006-up F-250 and F-350.