By Larry Carley
Technical Editor
The classic symptom of a wheel bearing that is failing is cyclic noise. Most often a bad bearing will produce a chirping sound or a growl that changes in proportion to vehicle speed.
If a bad bearing is suspected, the wheel bearings should be inspected to see if there is any play. On late-model vehicles with sealed wheel bearings or bearing cartridges, there should usually be little or no play.
To check a wheel bearing, grasp the tire at the 12 and 6 o’clock positions and attempt to rock the tire. If any play can be felt, the bearings are loose and need to be replaced.
Also, rotate the tire by hand. Any roughness or noise from the bearings would also tell you the bearings are worn or damaged and need to be replaced.
Bearing play can be measured by placing a dial indicator against the hub and turning the wheel. Refer to the vehicle manufacturers specifications, but as a rule no more than .005 inches of play is allowed for most sealed wheel bearing and hub assemblies.
If one wheel bearing is loose or noisy, pay close attention to all of the other hubs on the vehicle, too, especially if the vehicle has a lot of miles on it or has been driven through axle deep water or been flooded. Chances are some of the other wheel bearings may also need to be replaced.
Customers should be warned not to put off replacing a noisy or loose wheel bearing. A bearing failure can often cause the wheel (or rear axle in the case of a rear axle bearing) to separate from the vehicle. This would cause a loss of steering control that might have potentially deadly consequences!
