Your Guide to Packing Bearings

Anti-friction bearings make it possible for the wheels to rotate while they support the entire weight of the vehicle.

Bearings are quite small, but they can have a big impact on drivability when they start to fail. To prevent issues and unscheduled trips to the auto repair shop, you must keep the bearings lubricated.

What Does It Mean to Pack a Bearing?

To pack a bearing means to apply a substantial amount of grease throughout the entire bearing assembly. Packing is a part of bearing maintenance that aims to clean the bearings and keep them lubricated.

Like most car parts, manufacturers also recommend using vehicle-specific grease for bearing assemblies.

Grease is oil mixed with a thickening agent. It’s typically inserted in spaces where liquid lubricant won’t hold. In most cases, aluminum, barium, and calcium are the thickening agents added to the grease mix.

How to Pack Wheel Bearings On a Trailer

Packing a wheel bearing is a fairly easy task that even newbie DIYers can do in their garage. Here’s a general guide on how to pack a bearing.

Step 1: Hoist the vehicle safely before removing the wheel.

Step 2: For vehicles with a rotor/caliper setup, remove the brake caliper assembly. You can use a coat hanger or hook to support the assembly and prevent the caliper from hanging by the brake hose.

Step 3: Remove the grease cap, cotter key, and spindle nut.

Step 4: Remove the washer and outer wheel bearing.

Step 5: Remove the bearing hub from the spindle. The inner bearing will still be in the hub after this step, but you can remove it once the grease seal is pried out.

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Pro Tip: Pop out the seal by removing the hub assembly. Then, thread the nut back on a couple of turns, put the hub back over the nut, and place the inner bearing against the nut. It might take a couple of hits to let the nut hold the bearing and seal on the spindle.

Step 6: Use acetone to clean the bearings. You can also use other alternatives like denatured alcohol or brake cleaner.

Step 7: Make sure the bearing’s solvent layer is completely washed off and dry for the new grease to stick. Avoid using an air nozzle to blow out the bearings.

Step 8: Inspect the bearings and races for lines, scratches, or pits. Also, check the cage for straight sections. Replace as needed.

Step 9: Pack the cleaned or new bearing with grease.

Step 10: Place a thin layer of grease on the outer race and spindle. Make sure to cover the outer and inner bearing seat and shoulder at the grease seal seat.

Step 11: Use a seal driver to install a new grease seal.

Step 12: Place about three tablespoons of grease onto the grease cavity of each wheel hub. Place the rotor with the inner bearing and seal over the spindle. The grease seal should rest on the seal’s shoulder.

Step 13: Install the outer bearing and bearing washer.

Step 14: Install the spindle and nut and use a wrench to position the bearing in the race and onto the spindle.

Step 15: Loosen the nut while rotating the tire assembly, and install a new cotter key.

Step 16: Bend the key ends up and around the nut before using a rubber mallet to install the grease cap.

Step 17: Use brake cleaner and a shop cloth to clean the grease off the disc brakes, rotors, and drums to avoid damaging the friction lining and creating brake noise.

Methods of Packing a Wheel Bearing

There are several approaches to packing a wheel bearing. Here are three of the most common ones.

By Hand

Put some grease on your palm, then force the grease through the bearing. Excess grease should come out of the other side.

By Hand-Operated Bearing Packer

A hand-operated bearing packer is better to use than your palm and produces better results.

Using a Grease Gun Bearing Packer

This type of applicator can either be hand-powered or electric.

Grease Classifications By Color

Identification, marketing, and consistency are the primary reasons why grease comes in different colors.

Identification

Color variations can help you distinguish one type of grease from another based on their manufacturer. A trailer that frequently traverses over water might require a different type of grease known as marine grease.

Marketing

Some consumers are attracted to a certain color of grease一even when it doesn’t have anything to do with function.

Consistency

Adding color can help create a uniform consistency for grease produced in batches.

Common Mistakes When Packing Bearings

Packing bearings might seem like a fairly easy job, but there are some repercussions when it’s done incorrectly. Here are some common mistakes to avoid when packing bearings.

Using the Wrong Grease

Using the wrong grease increases the risk of exposing the bearings to metal-on-metal contact. Always use vehicle-specific grease when packing bearings.

Lubricating Bearings When It’s Too Late

One common mistake car owners commit is lubricating their bearings when they look worn out. Like other maintenance tasks, bearing lubrication should be based on time instead of physical condition.

It’s no secret that bearings won’t last forever, but staying dedicated to their maintenance schedule can keep them around for a long time.

Applying Too Much Lubricant

There’s such a thing as over-lubricating bearings.

Applying too much grease can cause the inner grease seal to fail, causing the grease to seep into the brakes.

Too much grease can also build pressure and cause the bearings to work harder. This can result in increased bearing temperature that could get high enough to separate the oils.

Bearing Diagnosis

A faulty wheel bearing greatly affects rolling resistance and wheel positioning. A defective wheel bearing will cause your vehicle to exhibit the following symptoms:

• Humming, rumbling, or growling noise that increases with speed.
• Rough steering response
• Looseness or excessive play in the steering wheel when driving over rough road surfaces
• Grinding noises
• Vehicle pulls to one side while braking

Key Takeaways

Bearings are small components that make a big difference when it comes to drivability. Although they’re not designed to last forever, packing them is one way to prevent premature wear.

This process typically involves cleaning the old bearings and applying a fresh coat of grease to keep them lubricated.

Unfortunately, there might be times when bearings are broken beyond repair, and grease won’t be able to restore their functionality. When this happens, your only option is to buy a set of new ones.

Replacing wheel bearings will also require you to replace the race that the bearing rides in.