What is a wheel bearing?
Your wheels spin around constantly as the car moves, and it’s the wheel bearings that permit that. There’s an axle, a short, round bar that’s attached to the wheel with lug nuts, that spins inside an assembly of small, barrel-shaped rollers or ball bearings. The entire wheel-bearing assembly is cased inside machined steel races, and packed with goopy lubricating grease. Rubber seals keep this grease inside the bearing and dirt and water out. Many newer cars use a sealed, cartridge-style bearing that’s preassembled at the factory, and can’t be serviced, adjusted or lubricated. Generally, old-school vehicles like rear-wheel-drive sedans and pickups use the simpler serviceable bearing, while newer front-wheel-drive and all-wheel-drive vehicles use cartridge-type bearings.
What are the symptoms of a failed wheel bearing?
Generally, a bad wheel bearing will cause a rumbling noise, particularly during moderate cornering, but also while driving in a straight line. A rumbling while turning right means a failed left-side bearing, and vice-versa. Generally, wheel bearings can be expected to last the life of the vehicle, or to fail within a few hundred miles of a hard curb strike. If you’ve bent or even seriously gouged a rim by hitting a curb at speed, start budgeting for a bearing replacement soon. As the bearing deteriorates, the noise will get worse. Because the wobbling from the loose bearing can push the brake pads back into the calipers, you may feel a low or spongy pedal. A mechanic can easily diagnose the problem with the car up on a lift by shaking the wheel back-and-forth and up-and-down by hand. More than a 1/16” of movement is indicative of a bearing that needs adjustment or replacement. Your mechanic should automatically check for wheel bearing slop whenever the car is up on the lift for any type of service.
What is the severity of a failed wheel bearing?
The affected wheel could literally fall off. You’d have had to ignore progressively accelerating symptoms for a while, by that point.
Catastrophic failure is possible if the failing bearing is the old-fashioned style that needs periodic adjustment and re-lubrication. Cartridge-style bearings generally fail less dramatically, but nonetheless could leave you with an inoperable vehicle, or even the possibility of losing control of the vehicle in traffic. Allowing the bearing to fail completely also stands the chance of damaging other expensive components like brake calipers and wheel-speed sensors.
The wheel bearing cost of some simpler bearings can be less than $35 for parts and an additional $50 or so for labor, including replacing the seal. That’s basically the same labor cost as cleaning, repacking and adjusting one of these old-school wheel bearings. Replacing a cartridge-style bearing can top $300 for the part, and $100 for labor. Part of the large replacement part cost is that the wheel-speed sensor is sometimes integrated into the bearing, driving up the price. These prices are for a single bearing. It’s usually safe to replace only one bearing that’s been damaged by a curb or pothole. If the bearings are simply worn, think hard about doing both sides at the same time. You also may be able to save some labor costs if your brake rotors and pads could use replacing at the same time.
Keep in mind, pricing will vary by location and your vehicle make and model. If you want to know the wheel bearing cost for your vehicle, start by using Openbay to compare service pricing from quality repair shops in your area.
Service article written by an ASE Master Technician