Several years ago, a friend called asking if I could help with her car. She told me that her car had been in the body shop due to an accident. When she got the car back it vibrated so badly that it was unsafe to drive at highway speeds. She had taken it back to the body shop and was told they had not done anything to affect the driveline and the work they did wouldn’t cause the condition she was experiencing.

I told her to bring the car over, and I would take it for a test drive. The steering wheel had a severe shake, and the car was definitely not safe to drive. I got the car back home and started checking the tires for bulges, missing wheel balance weights, etc. After not spotting anything obvious on the outside, I crawled under the car to check the inside of the wheels and tires. Again, nothing obvious. But, as I was about to shimmy out from under the car, I noticed a thick coating of mud on the wheels. I knocked off the mud and noticed that the other half of the wheel was clean. Aha! The source of imbalance. I grabbed a handful of quarters and took off for the car wash. I cleaned the wheels and good to go. The vibration was gone!

My friend drives on dirt (and muddy) roads. She had built up a thick, but apparently concentric, layer of mud on the inside of the wheels. The body shop had pressure washed the car before doing their repair and in the process removed only half of the mud from each wheel creating the imbalance. This provided a reminder that similarly, in the winter, chunks of snow and ice can be trapped on the inside of wheels and cause imbalance and vibration that can be fixed with a trip to the car wash.

Dave in Michigan

Noise, vibration and/or excessive steering wheel play are all signs that wheel bearings are worn out. Older vehicles have inner and outer wheel bearings/races that are usually easy to gently tap in place using hand tools. Many newer vehicles use wheel bearing and hub assemblies that simply bolt on as a complete unit. Wheel bearing replacement may get trickier when newer vehicles have a wheel bearing that is separate from the hub piece. Some vehicle designs have the complete wheel bearing and hub assemblies on one axle and have the wheel bearings separate from the hubs on the other axle.

When the wheel bearing and hub are separate parts, the wheel bearing is pressed into the steering knuckle, and the wheel hub is pressed into the wheel bearing. The wheel bearing may be a sealed unit or a bearing and race. Either way, the bearing is likely much more substantial than the relatively dainty inner and outer bearings/races on old cars. Specialized tools (Wheel Hub Removal Tool, Bearing Race & Seal Driver) are needed to press the old hub and old bearing out of the knuckle and then press in the new bearing and new hub. (Be sure to install the new wheel bearing so the correct (usually magnetic) side is nearest to the speed sensor.)

The repair is less likely to be successful or enjoyable if the knuckle is heavily corroded. Rusted surfaces make it harder to get the old parts off and less likely that bearing seals will properly seal. The ABS wheel speed sensor and other parts may be locked in place by rust, making removal and installation difficult.

Bearing and separate Hub that must be pressed into the knuckle (top), Bearing/Hub/Knuckle assembly with Brake Shoes (left), Bearing/Hub/Knuckle assembly with Ball Joint (right)

For many vehicles RockAuto has wheel bearing/hub/knuckle assemblies that include a new knuckle with the bearing and hub already installed. Other parts attached to the knuckle such as ball joints and even parking brake shoes are often included as well. Installing a completely new, clean wheel bearing/hub/knuckle assembly makes the job easier and faster for everyone. The reduction in labor costs will likely more than pay for the additional part cost, and the professional mechanic will be able to present the customer with a gleaming new hub, knuckle, dust shield, etc. rather than what may still look like shabby, rusty parts even after lots of tedious rust-battling elbow grease.

See the new wheel bearings, hubs, and bearing/hub/knuckle assemblies available for your specific vehicle under "Brake & Wheel Hub" in the RockAuto.com catalog. Just the knuckle may be found under "Steering." Be sure to consult your vehicle's repair manual (found under "Literature") for vehicle-specific repair instructions.

Tom Taylor,
RockAuto.com

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