Axle Bearing and Seal Replacement

Do you see gear oil leaking from the rear wheel? Is your vehicle making a roaring sound that follows the vehicle speed from the front or rear?  Do you wonder how difficult it is to change the front or rear axle seal and bearing or bearing hub? You have come to the right place. We are a team of ASE certified online mechanics that have created this guide for you to save you money while having the satisfaction of doing the job right.

Most vehicles axles bearing are basically the same and are either straight axle (rear), independent suspension (CV axle) or bearing hub styles. We have a complete list of these different styles of axle bearing replacements and an explanation for why they go bad and what happens when they do.

If you are not going to do the repair yourself this guide with videos will show you what you are paying for when you take your vehicle into a repair shop.

In This Guide

Why Does an Axle Bearing Fail?

A bearing is made of high grade steel which has a super hard coating over the rollers, inner and outer races. A bearing goes bad when this coating is worn away due to mileage or extreme load which just leaves the normal steel which then degrades and destroys the bearing components. Also, failures can occur when moisture combined with salt from roads penetrate the seal and contaminate the bearing, or over time the grease used to lubricate the bearing can liquefy leaving it dry causing a failure.

This is what a failed axle bearing looks like. You can see the roller cage is broken and there are pits on parts of the rollers themselves.

Here is a close up of the bad bearing roller. This is what happens when the bearing starts to fall apart. Parts of metal get caught up in-between the rollers and the upper and lower bearing race while under high pressure. This creates a grinding action which can be felt while driving the vehicle. These bearings are used in the front hubs and rear axles of all vehicles. Some CV axle bearings are actually two sets of ball bearings put together but fail the same way.

This is what happens to the bearing race once the bearing goes bad. Here is an example of what happens when the metal particles from the bad roller is pressed against the race under high pressure. A race in good shape will be smooth and flat, a machined surface.

What Happens When the Bearing Goes Bad?

When a bearing hub fails it allows the front wheel to wonder around causing irregular tire wear and steering characteristics. Another symptom of a failing bearing is a roaring sound that follows the vehicle's speed from either the front or rear end. A front bearing failure will change in tone when you steer the car right or left while the vehicle is in motion. A trick to locate a bad bearing on a front wheel drive car is to raise the front of the vehicle so the wheel are not touching the ground. While placing your hand on the coil spring spin the wheel rapidly. A bad bearing will give a distinct vibration if is it has failed.

A bad bearing will also allow the brake rotor to contact the brake pads and push them back into the caliper which will cause the bake pedal to go to the floor. If a bearing is bad and neglected it will cause the wheel to lock up in which case at this point the differential will most likely need to be replaced because the threads on the housing will be too badly damaged or the bearing will be melted onto it. It can also cause the wheel to fall off because the axle, hub or bearing will melt allowing the wheel, lug nuts and axle flange to become separated from the car.

When an axle bearing or bearing hub fails, it may cause the wheel to have play from top to bottom, but not always. Grasp the tire firmly and jog the wheel back and forth and from top to bottom to confirm the failure. On straight axle differential style of vehicles a bearing failure will be indicated by leaking gear oil.

Before You Begin the Job

Before you begin, park your car on level ground with the transmission in park. You will need to raise up your car with a floor jack and secure it using jack stands for safety and then remove and reinstall the wheel. Remember safety first, never get under the vehicle unless jack stands are in place. We want you to use safety as a normal practice anytime repairs need to be done as you learn automotive repair.

The brake caliper will need to be removed along with the caliper mount and the brake pads.

If you are not replacing the brake pads then you don't need to open the bleeder or push the piston back into the caliper for this job.

If the rear axle bearing and seal is being replaced you will be dealing with gear oil so have a fluid catch basin ready. Identify the side of the differential you see the leak or hear the noise on before performing the repair. Also, if the gear oil has been leaking for a while you will need to replace the emergency brake shoes. If one bearing has gone bad you should replace all of them. The effort of the job is in the labor, the bearings and seals don't cost that much comparatively speaking.

A complete list of tools, parts and repair manuals are at the end of this guide.

Wheel Bearing Hub Replacement

To get an idea on what you are in for with this repair please watch the video below and then read down through the guide to pick up on additional information which is updated regularly. Let's get started.

Step 1: Remove Bearing Hub Mounting Bolts

If the vehicle is equipped with ABS it will have a wheel speed sensor which will need to be disconnected before removing the bearing hub. Once this has been done locate and remove all axle bearing hub mounting bolts which is located behind the spindle. The hub will become loose.

Learn more: ABS wheel sensor connector removal

The bolts size is 15mm, 17mm and 18mm in most cases and will be fairly tight so be ready. Position the wrench or ratchet to push downward to loosen. If you are lifting upward it can hurt your back which is no fun especially when you have the reminder of the job to do.

Step 2: Match the New Bearing Hub

Once the old bearing has been removed, match the old bearing assemble to the new unit to ensure a proper installation. Always use a top quality factory (AC Delco, Ford, Chrysler) replacement parts because these bearings have added strain on them especially when you have large tires on the vehicle. The bearing below has an ABS sensor included.

Step 3: Installing the New Bearing Hub

While holding the new axle bearing hub, install the mounting bolts by hand to avoid cross threading.

Then, tighten evenly in a star pattern to manufacturers specifications (70-85 ft pounds). These bolts can be installed with thread lock for added protection against loosening. Reconnect the ABS wiring connector and reassemble the remainder of the job as described in the linked repairs above.

CV Axle Bearing Replacement and Spindle Removal

A CV axle bearing is one piece bearing that incases the inner and outer bearing into one race with seals at either end. Once disassembled, this bearing is removed by pressing the bearing from the front or rear spindle. These bearing will go bad much like any other bearing but the replacement is a little different.

Step 1: Remove the CV Axle Flange Nut

Once the steps in the above guides are complete you will end up with the vehicle looking like this. This is in the rear so you will have the emergency brake shoes present which wouldn't be there if the job is being done in the front. Use a pair of pliers or dikes to remove the bearing hub nut cotter pin. If air tools are not being used you will need to do this step with the car still on the ground to hold the wheel from spinning while loosening the nut. These bolts are fairly tight so you will need to use a breaker bar to loosen it.

Using a large socket remove the axle nut from the bearing hub, we are using air tools so it makes the job easier. They have rechargeable impact guns that don't use compressed air which cost about $70.00 on Amazon.

Once the nut is broken loose you can remove the nut completely.

This will expose the lock washer which will still be on the CV axle against the wheel hub. Use a small screwdriver or pick to help remove the washer.

Step 2: Remove the ABS Sensor and Parking Brake

If the vehicle is equipped with ABS the wheel speed sensor will need to be removed either at the mount or at the electrical connector. This is ensure the sensor does not get damaged during the repair. After removing the mounting bolt, grasp the sensor and remove it you might notice fine metal particles over the magnetic end of the sensor this is from the bearing failure and must be cleaned off before reinstalling the sensor.

Step 3: Remove the Parking Brake Cable

If doing this job on the rear (only) of the vehicle you must remove the emergency brake shoes and cable. Once the shoes and springs have been removed it is time to remove the cable from the backing plate. Locate and remove (release) the cable housing retainer clip. This step can vary by way of a multi fingered retainer which is released from the outside of the backing plate which is found on American built vehicles.

Grasp the emergency brake cable firmly and pull it outward from the backing plate, (Note: Pliers can be used to help in the removal).

Step 4: Remove Suspension Bolts

While using a wrench to back up the rear swing arm nut, use a socket to remove the through bolt.

Remove the forward swing arm bolts from the bearing housing knuckle.

Locate and remove the trailing arm mounting bolt from the lower spindle mount.

Using a sharp object such as a scribe, mark the location of the strut mounting bolts so they can be reassembled in the same location.

Mark the strut to spindle alignment which also helps preserve the rear camber adjustment if any (alignment).

Use a socket and wrench to loosen and remove the strut mounting bolts, (leave the top bolt in without the nut) the spindle can become loose so keep your hands on it.

Step 5: Remove the Spindle

After all mounting bolts have been removed, grasp the bearing housing and spindle and work it outward and away from the drive axle. The drive axle can get stuck and may need help by pushing it outward through the hub. At this point the spindle will be loose and then there are two options, either you can take the unit to a automotive machine shop or visit this guide to do the CV axle bearing replacement yourself.

Learn more: How to use a hydraulic press to replace a CV axle bearing

Step 6: Reinstall the Spindle

After the new bearing has been installed lift the assembly into place. Slide the upper strut bolt through the spindle bolt hole while feeding the axle through the wheel hub. Spin the hub to help align the axle splines.

Next, insert and tighten the lower trailing arm bolt using a wrench or socket. This bolt should be fairly tight, you can use thread lock to ensure it doesn't come loose during its operation.

Then align the rear swing arm bolt hole and install and tighten the bolt and nut assembly.

Install and tighten the front swing arm bolt and nut.

Finally install the bottom strut mounting bolts and nuts. Tighten both while keeping the scribed line in alignment with the strut to retain the camber adjustment. This should conclude the suspension arm reassembly portion of the repair. Double check all suspension arm bolts for tightness to ensure proper operation.

Step 7: Reinstall Parking Brake Cable

Install the parking brake cable into the backing plate housing, reinstall the retainer clip if equipped. On some designs the cable simply pops into place and is held in position by spring loaded retainer clips.

Step 8: Reinstall ABS Sensor

After cleaning the sensor free from metal particles, install it back into the spindle. Then install and tighten the mounting bolt and reattach the wiring harness into the retainer clips.

Step 9: Reinstall Axle Nut

After all suspension bolts are tight, reinstall the axle wheel hub washer. This washer is unidirectional and can be install either way. Sometimes these washers can be damaged in which case it should be replaced.

Then, install the axle nut by hand to avoid cross threading.

Using a torque wrench tighten the axle nut to manufacturers specifications (usually 140-180 torque pounds). This can be completed once the tire is on the ground to help hold the tire in place.

Once the nut gets close to the tightness desired, align the cotter pin holes for easy installation while reaching the proper torque.

Insert a new cotter pin, use dikes to bend and cut the long side of the pin to hold it in place. You are now all set, continue to reinstall the parking and disc brake assembly. Also reinstall the wheel and torque it to manufacturer specifications.

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