This video is sponsored by Schaeffler.
In our last video, we discussed diagnosing wheel bearing failure. All kinds of other things on a vehicle can make noises that appear to be coming from the wheel bearings. So, let’s cut through some of the issues that can lead to confusion in this video.
Let’s say there’s a possible wheel bearing complaint. It may not be so easy. If a vehicle is emitting a growling noise that’s more noticeable in a specific gear range, a worn bearing in the transmission may be causing the bearing noise. If the bearing noise is constant regardless of acceleration or deceleration and is approximately three times wheel speed in frequency, the faulty bearing would generally be found on the transmission output shaft or the driveshaft intermediate support bearing.
A popping or clicking noise when turning is a classic symptom of a bad outer CV joint. If the boot is torn or leaking, it should be replaced regardless of the condition of the joint. If the CV joint is noisy, get that thing out of there! it needs to be replaced.
Want to be a wheel bearing doctor? Some worn wheel bearings can often be detected by rocking the vehicle from side to side at low speeds with the steering wheel. This technique tends to increase the load on the bearings, causing the pitted bearing to become noisier than usual. This test works better when the vehicle is warm and in a parking area or roadway with light traffic where it’s absolutely safe to perform this test.
One tool that is helpful in diagnosing wheel bearings is a wired or wireless microphone/stethoscope that can be attached to a knuckle. Once an engineer-only tool, the prices for these microphone/stethoscopes have dropped dramatically.
While there are no set specifications for noise or standardized mounting points for the listening device, it can allow you to compare the bearing on each side and compare while on a test drive. These devices can also allow technicians to eliminate components that could be the source of cyclical noises like CV joints, brakes and differentials.
Well, that’s all for today. Hopefully, you’ve gained a little more insight into wheel bearing diagnostics. Keep those comments and questions coming! I’m Mark Phillips. And thanks for watching.
