What Is an Axle Bearing and What Are the Signs That It Is Worn Out?

Before we get into details about how to notice the signs of a worn axle bearing and how it can be fixed, we first need to understand what axle bearings are and what they do.

What Is an Axle Bearing?

The term axle bearing refers to a device located at each mounting end of a live axle, allowing it to spin without resistance or wear. 

Just to refresh your memory, first, there’s the car axle, which is the central shaft for a rotating gear or wheels. On wheeled vehicles, the axle can be fixed in two ways:

  • One in which the axle rotates with the wheels (referred to as live axle)
  • One in which the wheels rotate around the axles (referred to as dead axle)

In both cases, we need axle bearings in the following:

  • Mounting positions where the axle is supported 
  • Inside a central hole in the wheel or gear so that it rotates around the axle

What Do Axle Bearings Do?

Cars have countless components, and when they rub against each other, they produce friction, which leads to heat. To prevent excess heat from forming, either lubrication or bearings are used to reduce friction.

The axle and bearings help in maintaining the position of the wheels relative to each other and the vehicle. The axle serves as a driving torque to the wheel and supports the weight of the car, while the axle bearing ensures that the axle’s rotation is frictionless.

So, when these wheel bearings start to wear off or break down, drivers will begin noticing a significant difference in the drive.

Wearing of the Axle Bearing 

The wheel bearings can be found in either the front or rear, or both. Their constant spinning causes them to deteriorate after a while. Factor in the car’s weight and added cargo, and you get a car part that wears out relatively fast. 

Foreign contamination, loss of grease, and improper adjustment also cause the wheel bearings not to roll effectively and thus making the drive less smooth.

How Do You Know Your Axle Bearings Are Bad? 

Here are some signs that the wheel bearings are starting to wear out.

Signs that the Axle Bearings Are Worn Out

  1. Unusual Sounds – as the wheel bearings deteriorate, this leads to more friction between the components, and that inevitably leads to weird grinding noises that increase in volume as the speed of the car increases.
  2. Uneven Wear of the Tyres – when the wheel bearings start to fail, the corresponding tyre will start to wear unevenly from the rest too. 
  3. Vibrations on the Steering Wheel – at slower speeds, vibrations can be felt on the steering wheel if the wheel bearings have worn out badly.
  4. Wobble in the Wheels – you can test this by lifting the car with a jack. Rotate the tyres clockwise and anticlockwise to check for any sounds or resistance. Check the movement of the wheels by rocking back and forth. Unusual sounds and a lot of play indicate bad wheel bearings. 
  5. Steering Difficulty – when wheel bearings wear out, the steering becomes loose and less precise.
  6. Vehicle Pulls to the Side – corroded wheel bearings will cause the vehicle to vibrate when travelling on rough surfaces. Pulling to one side is also common, occurring mostly when you apply brakes. When that happens to you, the axle bearings to the side your car pulls to are likely worn out.

Worn-out bearings can also make the vehicle less responsive and wear the tyres faster. 

It is best to have the bearing assembly inspected by a trusted technician to avoid any hazards, such as wheel bearings coming loose. 

Axle Repair and Installation

Wheel bearings don’t deteriorate very quickly and may even go beyond 200,000 km without any issues. However, once a problem arises, you should act immediately to avoid further damage. 

A cost-effective approach is axle shaft repair bearing. In this procedure, the axle assembly replaces both the bearing and the conventional seal without requiring extra parts. 

Before attempting a new axle bearing installation, examine the old axle assembly for corrosion or any other complications that might hinder the repairing process.

Inspect the housing depth of the axle tube to see if the repair bearings can be used. The axle tube’s inside and outside diameters should be measured so that it compares to the width of the bearings. 

You must also check with the owner’s manual or manufacturer’s website to avoid any complications. Follow the instructions on how to disassemble it properly. 

Tips to Observe when Installing a New Axle Bearing

  • Use only fine-grade emery paper to clean the axle shaft.
  • Dip the new bearing in differential oil, and then remove the excess before installing.
  • The seal should be facing out when installing the bearing. When assembling, apply force to the bearing ring and not to the seal.
  • The re-installing process of the axle should be as recommended by the manufacturer.
  • Clean the differential housing before filling up with clean differential oil. 


It’s a good thing that axle bearings don’t deteriorate quickly, but if you own an old car, it’s to your advantage to know the signs so you can solve the issues as soon as they arise. If one of the axle bearings is damaged, it would be a good idea to check on the other too. 

(Blog from carpart.com.au)

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