A road test can usually indicate excessive wheel bearing noise. Sealed wheel bearings emit a howling sound when the bearings go bad. This sound is only present when the vehicle is moving. The sound is constant, unwavering and increases in loudness and pitch when vehicle speed increases. If wheel bearing noise cannot be positively diagnosed, or if the front or rear origin of the noise cannot be determined, perform the following wheel bearing test:

1. Raise the vehicle. Support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
2. Spin the wheels by hand. Inspect the wheels for the following conditions:

•	Out-of-round tires

•	Out-of-balance tires

•

Bent rims

•	Loose wheel bearings

3. On two-wheel drive vehicles, spin the front wheels using a commercial wheel spinner. Spin all the driven wheels using the engine.
4. If noise can be heard from the passenger compartment, replace the noisy wheel bearing's cartridge. Refer to Front Wheel Bearing and Hub Replacement in Front Suspension.
5. Lower the vehicle.

Tools Required

Perform the following test in order to inspect for play in the bearing cartridge assembly:

1. Raise the vehicle. Support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.



2. Remove the front or rear tire and wheel assemblies. Refer to Wheel Removal in Tires and Wheels.

2.1.	Reinstall two wheel nuts in order to hold the rotor tight.

2.2.	Compress the caliper piston in order to free the caliper assembly.

2.3.	Mount J 8001 and J 26900-13 on the front wheel hub.

2.4.	Push and pull the brake rotor by hand. If rotor movement exceeds 0.8 mm (0.03 in), replace the wheel bearing. Refer to Front Wheel Bearing and Hub Replacement in Front Suspension.




3. For drum brakes, use the following procedure:

3.1.	Remove the brake drum.

3.2.	Mount J 8001 and J 26900-13 on the rear hub unit.

3.3.	Push and pull the hub unit by hand. If the hub movement exceeds 0.8 mm (0.03 in), replace the wheel bearing.

4. Install the tire and wheel assemblies. Refer to Wheel Installation in Tires and Wheels.
5. Lower the vehicle.