DIY

How to Diagnose a Faulty Wheel Hub

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A lot of other car problems can mimic a faulty wheel hub assembly. So, before you dive into any repairs, you’ll want to diagnose the problem thoroughly.

On some vehicles, the hub and bearing are two separate parts. But in this article, we’ll focus on integrated wheel hub assemblies, which house both components together in a single unit.

Wheel Hub Inspection Methods

A good hub assembly should have close to zero lateral movement. If the wheel and tire assembly easily move back and forth, the hub is bad and must be replaced.

There are several ways to inspect a wheel hub assembly. In many instances, a hub bearing will make noise without having any noticeable play. That’s why it’s important to have a variety of troubleshooting tactics at your disposal.

Note: The following is for informational purposes only. Consult the factory information for repair instructions and recommended safety procedures.

1. Inspect for play

Some faulty wheel hub assemblies, but not all, will have noticeable play when rocked by hand. Use these steps to check your car:

A good hub assembly should have close to zero lateral movement. If the wheel and tire assembly easily move back and forth, the hub is bad and must be replaced.

2. Check for roughness

The bearings inside the hub assembly could be worn, even if the hub doesn’t have any play. In such a situation, the bearings will become rough and cause a growling noise while the car is in motion. You can easily check for this condition. Here’s how it’s done:

If roughness is felt, the hub assembly may need to be replaced. To get an idea of how much “roughness” is too much, compare rotational resistance among multiple wheel/tire assemblies.

Another method is to put your hand on the suspension coil spring while rotating the wheel/tire assembly. Extreme vibration felt through the coil indicates a bad hub assembly.

3. Listen for noise

Listening for wheel hub assembly noise should only be performed on a professional hoist. Running a car on jack stands is extremely dangerous. If the car were to pop off the stands, it could run you over.

You may be able to hear a faulty hub assembly, even though you can’t feel it. Running the vehicle in the air while listening to the wheel bearing area can pinpoint the problem. Keep in mind, this only works on hub assemblies located at the drive wheels.

Note: This test should only be performed on a professional hoist. Running a car on jack stands is extremely dangerous. If the car were to pop off the stands, it could run you over.

Should one hub assembly be significantly louder than the other, the noisier of the two should be replaced.

There’s also a more sophisticated noise test that involves using an electronic stethoscope, such as the Steelman Chassis Ear. The tool has individual mics that are placed at each wheel. Driving the car while listening to the chassis ears can pinpoint a faulty hub assembly.

4. Monitor for excess heat

Although this method isn’t the most accurate, it can occasionally prove useful. The more precise (and expensive) your infrared thermometer or thermal camera is, the better your results will be.

If one wheel hub assembly is significantly hotter than the others, you may have found the bad bearing.

5. Use a dial indicator

You won’t see this method performed much in shops, but it does pop up in textbooks. This process involves a measurement tool called a dial indicator, which you can use to check the hub assembly for excessive movement. Perform the following steps to complete the test:

Generally, there should be no more than .004″ of play [1]. For an exact specification, it’s a good idea to compare the reading to the information listed in the manufacturer’s repair manual. If the measurement you got is excessive, the hub assembly should be replaced.

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Author

Mia Bevacqua

Chief Mechanic

Mia Bevacqua has over 14 years of experience in the auto industry and holds a bachelor’s degree in automotive technology. Her knowledge has been applied to automotive software engineering, mechanical failure analysis inspections and, of course, writing. Instead of high-end cars, Mia prefers fixer-upper oddballs, like her 1987 Cavalier Z-24 and 1998 Astro Van AWD. Her dream car is a Citation X11.

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