As you can see in Figure 15-7, 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.
Tip: Before you check your bearings, consult your owner's manual or dealership to find out whether the bearings on your vehicle are sealed. If they are, you can't repack them.
- If you have drum brakes, it's important to check the bearings when you check your brakes to make sure that the grease hasn't 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 isn't terribly difficult, certain aspects of the job can create problems for a beginner. Because your brake system can kill you if it isn't assembled properly, I strongly suggest that if you want to do it yourself, you do the job under supervision at an auto class.
If they are, have your wheel bearings repacked immediately. If you need other brake work, have it done at the same time so that you don't have to pay for any duplicate labor involved.
From Auto Repair for Dummies, copyright © 2009 by Wiley Publishing, Inc., Indianapolis, Indiana. Used by arrangement with John Wiley & Sons, Inc.