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Repacking Front Wheel Bearings - Preventive PackingDirty Fun With Wheel Bearings From the April, 2009 issue of 4Wheel & Off-Road By Fred Williams Photography by Fred Williams
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Packing wheel bearings is one of our favorite things to do. OK, we're lying. It's a dirty, messy, tedious job, but a very important job all the same. The basic premise of a wheel bearing is a hub that rotates on a spindle. Your wheels attach to the hub and the spindle attaches to the axlehousing. Between the hub and the spindle are bearings, usually two sets-an inner and outer wheel bearing. These bearings are comprised of little rollers that are held in a cage. These rollers roll along between the cage that rests on the spindle and the race that is pressed into the hub. To keep these little rollers happy you have to bathe them in grease. The grease keeps everything rolling and cool, and it acts as a microscopic cushion between the bearing rollers and the race. If you go through water and contaminate the grease, get dirt in the grease, or don't change the grease regularly, it will eventually deteriorate until it doesn't do its job anymore. Then the bearings will heat up and eventually melt, weld, and burn up inside your hub, resulting in a very expensive fix. This can result in terrible handling in the best-case scenario. In the worst-case scenario, the hub could lock up, the wheel could fall off, and your 4x4 might just cruise off the edge of a high mountain cliff with you in it-with no wheel or brake to stop you. So either get dirty or risk death and destruction. Grease is cheap, bearings can last a long time with proper service, and packing wheel bearings is easy, so we decided a basic refresher course on packing bearings on a front axle was due. We did this to a Dodge Dana 60 front axle with dualie hubs, but the basics are the same no matter what front axle you have. Just take the time and keep your bearings happy. If your axle doesn't have rebuildable bearings, but rather unit bearings, we'll show you how to replace them in an upcoming Back to Basics.  1. The first step to rebuilding...  1. The first step to rebuilding your bearings is getting the hubs off your truck. Our front axle was already disassembled when we got it, but yours might not be. Throw the truck up on jackstands. Grab the top and bottom of the tire to see if you can get some in and out movement. If so, it's probably time for a rebuild or repack. Also, if you get a squealing noise while driving it might be your bearings slowly dying. To do a quick check after normal driving, touch the hub. If it's too hot to touch, then it's time for fresh grease and maybe more. And finally, if mud and water crossings are your thing, then definitely repack your bearings regularly, and you might want to step up to some quality waterproof marine-grade bearing grease.  2. On the inside of the hub...  2. On the inside of the hub is the hub seal. This must be removed and replaced. You can either use a long drift or block of wood and knock it out from the inside by using the inner bearing to push it, or you can use a seal puller. The seal is often destroyed in removal, but even if it's not, it should always be replaced.  3. Grease that's white or...  3. Grease that's white or milky has been contaminated with water. If it's gritty it has dirt or sand in it. If it's black it has probably been hot. All these mean that it's time for a cleaning and repack. Once you have the old bearings out, give them an inspection for wear, pitting, rust, or scarring. Check for cracked or broken bearing cages. The cage is the piece that holds all the rollers to the bearing. Slight discoloration isn't bad, but if it's dark like burnt metal, it's time to replace. If you're reusing the bearings, take the time to clean them with solvent and compressed air, but do not let the air spin the bearings because this can damage the rollers.  4. Some of our bearings looked...  4. Some of our bearings looked good enough to reuse, but to be safe we had all new inner and outer wheel bearings sent over by National Drivetrain. National also supplied us with new spindles, axle joints, spindle nuts, hub seals, and a kingpin rebuild kit. Check out our website for details of the other work done to this axle.  5. With both the inner and...  5. With both the inner and outer bearings removed, dig out all the old grease with a rag or towels. This is the messy step of the job, but required. We used our portable 5-gallon Oil Eater parts cleaner to soak the hubs in after the majority of the gunk was scraped off. The more you clean now the easier the rebuild. Don't be scared to scrub and scrub with an old brush.  6. Once the hubs are clean...  6. Once the hubs are clean and dry it's time to remove the old bearing races. This is done with a brass punch. Each race is pressed into the hub for a tight fit. If the race falls right out, you have a problem and may need to replace your hub. Once you have removed the old races, look for cracks, pits, or rust-again, replace if need be. Then clean the hubs some more and get all the old grease and grit out.  7. Now is a good time to paint...  7. Now is a good time to paint the outside of your hubs if you were planning to. After paint, we installed the wheel studs and bolted on the brake rotor. Our hub may look funny because it is a dualie front hub with a bolt-on rotor, whereas most hubs use the pressed-in wheel studs to hold the rotor.  8. This should give you an...  8. This should give you an idea of how the bearings and races work. The inner bearing is a little larger and it will slide over the spindle until it is tightly pressed onto the spindle. Then the bearings will roll around inside the cage between the inner race and the outer race, which is pressed into the hub. The outer bearing does the same thing, just farther out on the spindle.
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