Live Axle Wheel Bearing Replacement

Live Axle Wheel Bearing Replacement

Replacing wheel bearings on a vehicle with a live rear axle may not be one of the most regular jobs you do, but it can be one of the most profitable. While the basics have not changed in more than 60 years, new seal materials and differential designs have added new wrinkles.

Replacing wheel bearings on a vehicle with a live rear axle may not be one of the most regular jobs you do, but it can be one of the most profitable. While the basics have not changed in more than 60 years, new seal materials and differential designs have added new wrinkles.

Bearings

Replacing rear wheel bearings on a live axle rear suspension requires a few extra steps when compared to a unitized bearing. To remove the axle shaft, the differential must be accessed, and the clips that hold the axle in the differential must be removed.

There are three bearing styles — Conrad, roller and ball. Most axles use these types of bearings in a cartridge-type arrangement. They are installed into the axle ends or pressed onto the shaft and possibly held in place with a pressed-on retainer. On some axles, the bore on the housing is tapered, and the bearing will fit in only one direction. This is where measuring tools can save you time and maybe multiple part deliveries.

Some axles use a “floating” axle shaft design. This design takes the weight of the vehicle off the axle, so all it has to do is transmit power. This allows the hub of the axle to carry a higher load. Some of these axles use tapered roller bearings. Another advantage of a floating axle is if the axle separates from the differential or flange, the wheel will not fall off the axle.

The most critical part of the disassembly is removing the bearing and retainer from the shaft without damaging the axle shaft or housing. Any damage to the surfaces that the seal or bearing ride on can cause premature failure of the new bearing.

Another rookie mistake made by some technicians is installing the parts in the wrong order. It is not uncommon to press the new bearing onto the axle only to realize the flange plate was not installed. This also applies to the tone ring that might be on the ring gear.

Look at the differential cover before you quote the job. On snow-belt vehicles, the differential cover is prone to rust. Perforation does happen, but chances are better that prying on the weakened cover may distort it to the point that it will never seal. Replacement covers are readily available and very economical.

Seals

The leading killer of solid axle wheel bearings is a failed seal. Most seals ride on the axle shaft, and they typically have a lip and a spring that holds the lip to the axle. When a seal is installed, take your time installing the axle. Splines can damage the seal and cause leaks.

The area on the axle shaft where the seal and bearings make contact is the most important. It must be free of rust and imperfections. Use only a fine-grade emery paper to clean the axle shaft between the flange and the worn area.

If the surface is grooved or damaged, the axle can be repaired with a sleeve on some applications. If not, the axle should be replaced. Another option for some applications is to install a replacement bearing that repositions the bearing and seal to ride on unworn surfaces.

Make sure the seal is installed in the correct position. A correctly installed bearing may extend out from the housing up to 1/4″. Some axles have small seals that must be appropriately positioned so pressures can be vented and the lip can work.

Make sure the breathers on the axle are not clogged. The breather on some axles acts as a PCV valve to keep pressures within a certain range so the seals can work their best as the differential heats and cools. If a breather is clogged, the heat will increase pressure in the axle. As the axle cools, negative pressure could build up behind the seal. These changes in pressure will cause the lips of the seals to deform and leak.

Any leak on an axle should be taken seriously. Ignoring a leak can be very expensive and destroy the bearings, brakes and differential.

Make sure to use the correct gear lube. Some differentials require a specific friction modifier additive package that might be included in the gear lube, or you might have to add it separately. If the wrong lube is used, it might cause noise and damage to the friction plates inside the limited-slip mechanism.

You May Also Like

Brake Problems

Reducing brake drag on late-model vehicles is not accomplished by a single component; it takes a system.

Drivers and technicians rarely make the connection between fuel economy and brakes. Moving the pads back from the rotor by only 1mm can increase fuel economy by as much as three to five percent. For engineers, it is a huge gain that does not involve exotic materials or adding expensive components.

The Real Cost of Installing Cheap Brake Pads

The brake repair market is starting to become dominated by a “good enough” mentality.

Brake Boosters and Start/Stop Vehicles

For a vacuum brake booster to work, it needs a source of vacuum.

Wheel Speed Sensor and Hub Unit Diagnostics

All wheel speed sensor codes are just the starting points of a diagnosis and not a reason to order a part.

Better Brake Law Update

Learn the latest about the salmon-inspired law.

Other Posts

Live Axle Wheel Bearing Service

Replacing rear wheel bearings on a live axle rear suspension requires a few extra steps when compared to a unitized bearing.

Wheel Bearings Components

Follow along to learn what you may encounter when dealing with a Gen 1 wheel bearing. This video is sponsored by The Group Training Academy.

Axle Torque Procedures

Guessing the correct torque setting is a bad idea.

Top 10 Brake Mistakes

Here are the top 10 brake mistakes technicians can make.