What are the signs that a wheel bearing has been damaged by a pothole? And how do you inspect a seal on a wheel bearing hub unit?
Click here to read more
To answer the first question, when a bearing hits a pothole, it actually causes a small indentation on one of the races. Over time, this small indentation causes turbulence in the fat over this area. This is called a Brinell mark. This is where something very hard makes its mark in this race over time as the benchmarks pass through it.
It brews fat and that mark can get bigger and bigger. So over time, it causes noise. It may take three days, or three weeks, or even three months, depending on the vehicle, but the main symptom will be noise coming from the wheels locking. There may be no detectable change in clearance or play in any direction of the wheel, but it’s going to be very, very loud.
Regarding the second question on how to inspect a seal on a hub, the most important thing to remember is that there should be no grease leaks on the seal, especially on a modern hub. It could be a Gen 2, Gen 1, or Gen 3. If the seal is leaking, that’s a sign that the outside is going into the bearing, because if grease is leaking due to excess heat, that could be caused by Brinell inside the bearing, this is a sign that the bearing has suffered an internal failure.
So any time you see leaks or any time you install a wheel bearing and the seal separates from the outer race, the wheel hub or bearing needs to be replaced.
This video is sponsored by GMB.