You can check your car's wheel bearings to see if they need to be repacked. Wheel bearings usually come in pairs of inner and outer bearings. They allow your wheels to turn freely over thousands of miles by cushioning the contact between the wheel and the spindle it sits on with frictionless bearings and lots of nice, gooey grease. This grease tends to pick up dust, dirt, and little particles of metal, even though the bearings are protected to some extent by the hub and the brake drum or disc.
Usually, only the non-drive wheels (that is, the front wheels on rear-wheel drive vehicles and the rear wheels on front-wheel drive vehicles) have repackable wheel bearings. Vehicles with front-wheel drive have sealed front bearings, but some have packable rear ones. The bearings on four-wheel drive vehicles are quite complicated and should be repacked professionally.
Before you check your bearings, consult your ownerís manual or dealership to find out whether the bearings on your vehicle are sealed. If they are, you canít repack them.
If you have drum brakes: Itís important to check the bearings when you check your brakes to make sure that the grease hasnít become fouled. If it has, the particles act abrasively to wear away the very connection the bearings are designed to protect, and the result is a noisy, grinding ride. In extreme cases, you could even lose the wheel! If the bearings look cruddy, either repack them yourself or get a professional to do it.
If you have disc brakes: You have to remove the caliper to get at the bearings. Although this task isnít terribly difficult, certain aspects of the job can create problems for a beginner. Because your brake system can kill you if it isnít assembled properly, you might want to do the job under supervision at an auto class.
If you just want to check your wheel bearings for wear without removing the wheels, do the following:
Jack up your vehicle.
Support it on jack stands.
Without getting under the vehicle, grasp each wheel at the top and bottom and attempt to rock it.
There should be minimal movement. Excessive play may indicate that the wheel bearing is worn and needs adjustment or replacement.
Put the gearshift in Neutral if you have an automatic transmission, or take your manual transmission out of gear.
Rotate the wheel.
Listen for any unusual noise and feel for any roughness as it rotates, which may indicate that the bearing is damaged and needs to be replaced.
Shift back into Park (for an automatic transmission) or gear (for a manual transmission) before lowering the vehicle to the ground.