Ford Super Duty 4WD Front Wheel Hub Seal Kit 600-135

A 2008-2012 Ford F-250, F-350, F-450 or F-550 Super Duty that will not stay in four-wheel drive, grinds when the front hubs engage, or has rusty water in a front wheel bearing usually has the same root cause: a front hub seal or locking hub O-ring that has stopped sealing. This is the Dorman 600-135 wheel hub seal kit, which replaces every seal, O-ring and gasket at one front wheel, plus the small hardware that tends to get damaged during teardown. One kit does one side, so buy two if both hubs are coming apart.

What the hub seal kit does on a Super Duty

The front hubs on these trucks lock with vacuum. When you select 4WD, vacuum is applied to the locking hub and it couples the axle shaft to the wheel hub; in 2WD the hub releases so the front axle shafts are not spun at highway speed. That only works if the hub holds vacuum. The axle seal and hub seal also keep water, mud and road grit out of the unit bearing. Dorman's description for this kit says the parts are there to protect the locking hubs from moisture and contaminants so the truck shifts in and out of 4WD smoothly. Once a seal hardens, a lip tears or an O-ring flattens, vacuum leaks down and water gets in.

Symptoms of a leaking front hub seal

• The 4x4 indicator comes on but the front axle does not drive, or the truck drops out of 4WD after a few minutes
• Grinding or ratcheting from one front wheel when 4WD is selected
• A front hub that engages on one side only
• Rust-colored grease, water or a growl from a front wheel bearing
• Gear oil seeping past the axle seal at the knuckle

Ford issued a service message for 2005-2020 Super Duty 4x4 trucks used in extreme dust, mud or tar sand, noting accelerated wear of the 4x4 vacuum hub seal and wheel bearing. If your truck works in those conditions, plan on doing the seals whenever a hub is apart.

How to confirm before you buy

Put a hand vacuum pump on the hub supply line at the wheel and pull vacuum. If it bleeds down, the leak is at that hub. If both hubs hold vacuum, check the vacuum supply under the hood and the lines along the frame before buying seals. Also check bearing play with the wheel off the ground; if the unit bearing is loose or rough, replace it on the same teardown and install this kit at the same time.

Fitment

The kit is listed for 2008-2012 Ford F-250, F-350, F-450 and F-550 Super Duty trucks with 4WD, one wheel per kit. Dorman cross-references it to Ford numbers 5C3Z-1012-AA, 5C3Z-1K106-AB, 5C3Z-3254-AA, 5C3Z-3K050-AA, 5C3Z-4A322-AA, 9L8Z-4022-A and AC3Z-1S175-A. Retail catalogs show some F-450 and F-550 chassis listed with notes by axle, so compare the old axle seal and hub seal against the new parts before you start pressing, or send us your year and VIN and we will check it.

Install notes

• Remove the locking hub, then the hub nuts and snap ring. The Lisle 38700 spindle snap ring pliers are made for the snap ring inside the Super Duty hub bore.
• A rusted unit bearing often needs a puller; a slide hammer puller set or a forged hub puller saves the knuckle from a hammer.
• Clean the knuckle bore and the hub pilot to bare metal so the new seals sit square.
• Lube every seal lip and O-ring, then drive the seals with a flat driver from a bearing race and seal driver set so the case does not cock in the bore.
• Use the new hub nuts and screws and torque them to Ford's spec with a click torque wrench, then vacuum-test the hub before the wheel goes back on.

Does one kit do both front wheels?

No. The 600-135 services one wheel. Buy two kits if you are resealing both front hubs.

What is included?

An axle seal, a hub seal, two locking hub O-rings, a locking hub gasket, three locking hub screws, four hub nuts, a hub O-ring, a threaded valve fitting and a snap ring.

Will it fit a 2007 or 2013 Super Duty?

It is listed for 2008-2012 4WD F-250 through F-550 trucks only. Other years use different parts, so send us your year and VIN before ordering for a truck outside that range.

My truck drops out of 4WD. Is it always the hub seals?

No. Vacuum can also be lost at the supply solenoid or a cracked line. Vacuum-test each hub at the wheel first; if a hub will not hold vacuum, the seals or O-rings in that hub are the likely leak.

Should I replace the wheel bearing at the same time?

If the bearing has play, noise or water-contaminated grease, yes. The hub is already apart, and a new bearing behind old seals, or new seals in front of a wet bearing, is a repeat repair.