Since the invention of the modern vehicle, wheel bearings have been used in some capacity to allow the tires and wheels to spin freely as the vehicle moves forward or in reverse. Although the construction, design and materials used today are quite different than in years past, the basic concept of needing proper lubrication in order to work efficiently remains.
Wheel bearings are designed to last a long time; eventually, however, they lose their lubricity due to excess heat or debris that somehow finds its way into the center of the wheel hub where they are located. If they are not cleaned and repacked, they wear out and need to be replaced. If they break entirely, it causes a wheel/tire combination to fall off the car while driving, a very dangerous situation.
Before 1997, most vehicles sold in the United States were designed with an inner and outer bearing on each wheel usually serviced every 30,000 miles. "Maintenance free" single wheel bearings designed to extend the life of wheel bearings without having to be serviced eventually took over.
Although many of the vehicles on the road have this new style of wheel bearing, older vehicles still need them serviced, which includes cleaning and repacking the wheel bearing with fresh grease. Most automotive manufacturers agree that wheel bearing repacking and cleaning should be completed every 30,000 miles or once every other year. The reason for this is that eventually grease loses a lot of its lubricity due to age and heat. It's also very common for dirt and debris to seep into the wheel bearing housing either due to brake dust or other contaminants near the wheel hub.
We will address the general instructions for cleaning and repacking wheel bearings that are not worn out. In the sections below, we will articulate the symptoms of a worn out wheel bearing. If you notice any of these symptoms, it is recommended to replace the bearings as opposed to simply cleaning the old ones. It's also a good idea to purchase a service manual for your vehicle to learn the precise steps for locating and replacing this component on your vehicle, as it can vary based on individual vehicles.
Part 1 of 3: Determining the symptoms of a dirty or worn out wheel bearings
When a wheel bearing is properly packed with grease, it spins freely and without developing excess heat. The wheel bearings are inserted inside the wheel hub, which secures the wheel and tire to the vehicle. The interior of the wheel bearing is attached to the drive shaft (on front wheel, rear wheel and four-wheel drive vehicles) or spins freely on a non-drive axle. When the wheel bearing fails, it's often due to the loss of lubricity inside the wheel bearing housing.
If the wheel bearing is damaged, it displays a few warning signs or symptoms that alert the vehicle owner to replace the wheel bearings as opposed to simply cleaning and repacking them. Abnormal tire wear: When the wheel bearing is loose or worn out, it causes the tire and wheel not to align on the hub properly. In many cases, this leads to excessive tire wear on the inside or outside edge of the tires. There are several mechanical problems that can also display similar symptoms including over or under inflated tires, worn out CV joints, damaged shocks or struts, and suspension out of alignment.
If you're in the process of removing, cleaning and repacking the wheel bearings and you find excessive tire wear, consider replacing the wheel bearings as preventative maintenance. Grinding or roaring noise coming from the tire area: This symptom is commonly caused due to excess heat that has built up inside the wheel bearing and a loss of lubricity. The grinding sound is metal to metal contact. In most cases, you'll hear the sound from one side of the vehicle as it's very rare that the wheel bearings on both side wear out at the same time. If you notice this symptom, do not clean and repack the wheel bearings; replace both of them on the same axle.
Steering wheel vibration: When the wheel bearings are damaged, the wheel and tire are very loose on the hub. This creates a bouncing effect causing the steering wheel to vibrate as the vehicle accelerates. Unlike a tire balance problem that typically shows up at higher speeds, a vibration in the steering wheel thanks to a worn out wheel bearing is noticed at slower speeds and progressively gets worse as the vehicle accelerates.
It's also very common for the vehicle to have wheel-drive and acceleration problems when wheel bearings on drive axles are damaged. In any case, if the symptoms above appear, it's recommended to replace the wheel bearings as simply cleaning and repacking them will not solve the problems.
Part 2 of 3: Buying quality wheel bearings
Although many DIY mechanics often look for the best deal on replacement parts, wheel bearings are not components that you want to skimp on details or product quality. The wheel bearing is responsible for supporting the weight of the vehicle while also powering and steering the vehicle in the right direction. Replacement wheel bearings need to be made of quality materials and by reliable manufacturers. In most cases, the best option is to buy OEM wheel bearings for consistency. However, there are several aftermarket part manufacturers that have designed exceptional replacement parts that are superior to the OEM equivalent.
Anytime you are planning to clean and repack the wheel bearings, consider completing the following steps first to save you time, effort, and money in the long run.
Step 1: Look for symptoms indicating the wheel bearings need to be replaced. A wheel bearing must be in good working order, clean, have no debris, and the seals must be intact and working well.
Remember the golden rule of wheel bearings: when in doubt, swap them out.
Step 2: Contact the vehicle manufacturer's parts division. In regards to wheel bearings, most of the time, the OEM option is best.
There are a few aftermarket part manufacturers that make exceptional equivalent products, but OEM is always best for wheel bearings.
Step 3: Make sure replacement parts are for exact year, make and model. Contrary to what the local auto parts store might say, not all wheel bearings for the same manufacturer are identical.
It's very important to make sure you get the exact recommended replacement part for the year, make, model, and in many cases, package option for the vehicle you are servicing. Also, when you buy replacement bearings make sure you use the recommended bearing grease for packing the bearings. You can often find this information in a vehicle service manual.
Over time, the wheel bearings take a tremendous amount of abuse. Although they are designed to last more than 100,000 miles, if they are not routinely cleaned and repacked, they can wear out prematurely. Even with consistent service and maintenance, they eventually will wear out. Another rule of thumb is to always replace wheel bearings every 100,000 miles as part of routine maintenance.
Part 3 of 3: Cleaning and repacking wheel bearings
The job of cleaning and repacking wheel bearings is one that most DIY mechanics don't really like to complete for one simple reason – it's a messy job. In order to remove the wheel bearings, clean them, and repack them with grease, you'll have to make sure the vehicle is raised and that you have plenty of room to work under and around the entire wheel hub. It's always a good idea to clean and repack wheel bearings on the same axle the same day or during the same service.
In order to complete this service, you'll need to gather the following materials:
Clean shop rags
Pliers - adjustable and needle-nose
Replacement cotter pins
Replacement inner wheel bearing seals
Replacement wheel bearings
Safety latex gloves
Wrench and socket set
Warning: It is always best to purchase and review the vehicle service manual for your specific make, year, and model to complete this process. Once you've reviewed the exact instructions, only proceed if you are 100% confident in completing this task. If you are not sure about cleaning and repacking your wheel bearings, contact one of our local ASE certified mechanics to complete this service for you.
The steps for removing, cleaning and repacking wheel bearings are rather easy to complete for the experienced DIY mechanic. In most cases, you can complete each wheel bearing within two to three hours each. As noted above, it's critical for you to service both sides of the same axle during the same service (or before putting the vehicle back into service). The steps noted below are GENERAL in nature, so always refer to your service manual for exact steps and procedures.
Step 1: Remove the battery cables. On many vehicles, there are sensors attached to the wheels (ABS system and speedometer) that are supplied by power from the battery.
It's always a good idea to remove the battery cables before removing any components that are electrical in nature. Remove the positive and negative terminals first before raising the vehicle.
Step 2: Raise vehicle on hydraulic lift or on jack stands. If you have access to a hydraulic lift, use it.
It's much easier to complete this job while standing up. However, if you don't have a hydraulic lift, you can service your wheel bearings by raising the vehicle on jack stands. Make sure to use wheel chocks on the other wheels not lifted and always raise the vehicle on a pair of jacks on the same axle.
Step 3: Remove the wheel from the hub. After the vehicle is raised, start on one side and complete the side before moving onto the other.
The first step here is to remove the wheel from the hub. Use an impact wrench and socket or a star wrench to remove the lug nuts from the wheel. Once that's done, remove the wheel and place it aside and clearly out of your work area for now.
Step 4: Remove the brake caliper from the hub. In order to remove the center hub and clean the wheel bearings, you'll have to remove the brake caliper.
As each vehicle is unique, the process is just as unique. Follow the steps in your service manual for removing the brake caliper. Do NOT remove brake lines during this step.
Step 5: Remove the outer wheel hub cover. When the brake calipers and brake pads have been removed, you'll need to remove the wheel bearing cover.
Before you remove this part, inspect the outer seal on the cover for damage. If the seal has been broken, that's an indication that the wheel bearing is damaged inside. The inner seal of the wheel bearing is more critical, but if this outer cap is damaged, it should be replaced. You should proceed to purchase new bearings and replace both wheel bearings on the same axle. Using a pair of adjustable pliers, grab the sides of the cover and carefully rock back and forward until the center seal is broken. After the seal has been broken, remove the cover and place aside.
- Tip: A good mechanic usually follows a procedure that helps them keep all parts in a controlled area. A tip to consider is to set up a staging area with a shop rag where you place parts as they are removed and in the order in which they are removed. Not only does this help reduce parts being lost, but it also helps to remind you of the installation order.
Step 6: Remove the center cotter pin. Once the wheel bearing cover has been removed, the center wheel hub nut and a cotter pin will be visible.
As the image above indicates, you'll need to remove this cotter pin before taking the wheel hub off the spindle. To remove the cotter pin, use a pair of needle-nose pliers to bend the pin straight and then grab the other end of the cotter pin with the pliers and pull upward to remove.
Set the cotter pin aside, but always replace with a new one anytime you clean and repack wheel bearings.
Step 7: Remove center hub nut. To remove the center hub nut, you'll need a fitting socket and ratchet.
Loosen the nut with the socket and ratchet and manually spin the nut off the spindle. Place the nut on the same shop rag as your center cap to ensure they are not lost or misplaced. After the nut has been removed, you'll need to remove the hub from the spindle.
There is also a nut and outer bearing that comes off the spindle as you remove the hub. The inner bearing will remain intact inside the hub as you remove it. Pull the hub off the spindle when you've removed the nut, and place the washer and outer wheel bearing on the same rag as the nut and cover.
Step 8: Remove the inner seal and wheel bearing. Some mechanics believe in the old "place the nut on the spindle and remove the inner wheel bearing” trick, but that's really not a good way to do this.
Instead, using a flathead screwdriver, carefully pry the inner seal from the inside of the wheel hub. Once the seal is removed, use a punch to remove the inner bearing from the hub. As with the other parts you've removed, place them on the same rag when this step has been completed.
Step 9: Clean the wheel bearings and spindle. The best way to clean wheel bearings and the spindle of the axle is to remove all old grease with shop rags or disposable paper towels. This takes some time and can get quite messy, so make sure you use latex rubber gloves to protect your hands from exposure to chemicals.
Once all the excess grease has been removed, you'll need to spray liberal amounts of brake cleaner inside the wheel bearings to remove excess debris from the inner bearing "wheels." Make sure to complete this step for both inner and outer bearings. The inner and outer wheel bearings, the inner wheel hub, and the wheel spindle need to be cleaned in this method as well.
Step 10: Pack the bearings, spindle and center hub with grease. Not all greases are the same, so you should always verify that the grease you use is made for wheel bearings. Tier 1 quality moly EP grease is best suited for this application. Essentially, you want to work the new grease into every nook and cranny of the wheel bearing on all sides. This process can be very messy and, in some ways, ineffective.
To complete this step, there are a few tricks. To pack the wheel bearings, place the clean bearing inside of a plastic zip lock bag along with a liberal amount of new wheel bearing grease. This allows you to work the grease into each small wheel and bearing without causing a lot of mess outside of the work area. Do this for both the inner and outer wheel bearings Step 11: Apply fresh grease to the wheel spindle.
Make sure you have a visible layer of grease along the entire spindle, from the front to the backing plate.
Step 12: Apply fresh grease inside the wheel hub. Make sure the outer edges are fully covered before inserting the inner bearing and installing the new bearing seal gasket.
Step 13: Install the inner bearing and inner seal. This should be rather easy since the area has been cleaned.
When you press the inner seal into place, it will snap into position.
Once you've inserted the inner bearing, you want to spread a liberal amount of grease along the inside of those parts as the image above displays. Install the inner seal once the entire area has been fully packed with new grease.
Step 14: Install the hub, outer bearing, washer and nut. This process is in reverse of the removal so the general steps are as follows.
Insert the outer bearing inside the center hub, and insert the washer or retainer to align the outer bearing straight onto the hub. Place the center nut on the spindle and tighten until the center hole is aligned with the spindle hole. This is where the new cotter pin is inserted. Insert the cotter pin and bend the bottom portion upward, supporting the spindle.
Step 15: Spin the rotor and hub to test for noise and smoothness. When you've correctly packed and installed the clean bearings, you should be able to freely spin the rotor without hearing a sound.
It should be smooth and free spinning.
Step 16: Install brake calipers and pads.
Step 17: Install wheel and tire.
Step 18: Complete other side of the vehicle.
Step 19: Lower the vehicle.
Step 20: Torque both wheels to manufacturer’s recommended settings.
Step 21: Reinstall battery cables.
Step 22: Test the repair. Take the vehicle for a short test drive and make sure the vehicle turns left and right easily.
You want to listen carefully for any signs of grinding or clicking, as that may indicate that the bearings are not installed straight on the hub. If you notice this, return home and double check all steps noted above.
If you've read these instructions, reviewed the service manual, and have determined that you'd rather have a professional complete this service for you, contact one of YourMechanic’s local ASE certified mechanics to complete the wheel bearing cleaning and repacking for you.
This article originally appeared on YourMechanic.com as How to Clean and Repack Wheel Bearings and was authored by Tim Charlet.