In this page we’ll share what we’ve learned about wheel bearings and wheel bearing replacement during our 40+ years running an auto repair shop in Berkeley. Who might want to read this page? Maybe you if:
- Someone said you have a bad wheel bearing
- You’re hearing a noise you think is a wheel bearing
- You’d like to know what wheel bearings brands are good
- You’re wondering what’ll happen if you don’t replace a bad wheel bearing
If you’re local to Berkeley or the East Bay Area, and you own a Toyota, Honda, Subaru, Mazda, we’d be happy to help you with your wheel bearing replacement. If not, hopefully you’ll find some value in this article.
Table of contents
- What is a Wheel Bearing?
- Symptoms of a Failing Wheel Bearing
- What Causes Wheel Bearing Failure?
- What Happens if You Don’t Replace a Bad Wheel Bearing?
- What Brand of Wheel Bearing is the Best?
- How Can I Be Sure The Wheel Bearing Is Making The Noise I’m Hearing
- How to Replace a Wheel Bearing
- Wheel Bearing Replacement Pitfalls
- In Berkeley? Wheel Bearing Replacement Questions?
What is a Wheel Bearing?
A wheel bearing allows rotating wheel assembly to be firmly attached to the vehicle’s knuckle while allowing the wheel to rotate with very low friction. This is accomplished by placing perfectly round smooth metal balls between two “races”. The outer race is pressed into the knuckle and is stationary. The inner race spins with the wheel assembly.
Most cars use pre-assembled and lubricated bearings known as double row deep groove ball bearings or pre-assembled tapered roller bearings these days.
The most common type of bearing is a “cartridge bearing” which are sealed and lubricated at the factory. We remove the this type of bearing by pressing it out of the knuckle, and typically the knuckle must be removed from the car.
We do have tools designed to remove cartridge bearings with the knuckle still in the car, but if a bearing is at all stuck they may not work. A press will work 99% of the time.
Some vehicles use “hub unit bearings”, which contain both the bearing and the hub. This type of wheel bearing is typically easier to install because it can be unbolted from the knuckle and doesn’t need to be pressed out. You’ll see what I’m talking about a little later.
Older rear wheel drive cars used tapered roller bearings which required assembly, packing with grease, and periodic adjustment. These days bearings require no lubrication or adjustment of any kind. If the lubrication wears out, the bearing fails and is replaced.
Symptoms of a Failing Wheel Bearing
When wheel bearings go bad, they nearly always give plenty of advanced warning before causing a breakdown. Here are some wheel bearings symptoms to look for:
- Droning, humming, or rumbling noise at ~30MPH or more
- Creaking when braking or turning at low speed
- A click or pop when load shifts at low speed
- Wandering when trying to drive straight
- ABS light illuminated
- Low brake pedal on first application
What Causes Wheel Bearing Failure?
Nothing lasts forever, including wheel bearings, so it’s normal for wheel bearings to fail. Some cars, like some generations of Subaru need more frequent wheel bearing replacement than other cars. However, there are some things that will damage wheel bearings, so avoid them if you can. These are some of this things that can cause wheel bearing damage:
- Sharp impacts like curbs, potholes, and collisions
- Water intrusion. Especially avoid parking in the ocean
- Oversize and offset aftermarket wheels
What Happens if You Don’t Replace a Bad Wheel Bearing?
Unlike many automotive noises, symptoms of a failed wheel bearing should be investigated and addressed, not ignored. In the most extreme case, a wheel could fall off the car. However, none of our customers have ever had that happen and we’ve been doing this for 44 years.
As the wheel bearing gets worse, the symptoms will get worse and most reasonable people will address this issue before it gets out of hand.
What Brand of Wheel Bearing is the Best?
When in doubt, buying a wheel bearing from a dealership is nearly always a safe bet, but there are better deals to be had while still getting the same quality. Here are the brands we like for Japanese cars:
Brands We Like
- NSK – They’ve been making wheel bearings since 1916 and are used by many Japanese auto manufacturers.
- Koyo – They’re about 20 years old but they have a great reputation (which is well deserved). They also make bearings for Japanese auto manufacturers
- NTN – NTN is the third largest bearing manufacturer in the world and the largest in Japan and many of the bearings in your Japanese vehicle will be NTN.
- SKF – Unlike the other three, SKF is a Swedish company. The make great bearings, but usually not for Japanese auto manufacturers.
Brands We Avoid
Just because we don’t use these bearing that doesn’t mean they don’t make good bearings, they’re just not a good fit for the products that we work on.
- Timken – Timken is America’s oldest bearing manufacturer, founded in 1899. But they primarily make bearings for heavy duty applications, and have limited coverage for Japanese vehicles.
- GMB – GMB is a Korean brand and we’ve had issues with their water pumps (bearing failure) and timing belt tensioners (also bearing failure). This was many years ago and they may have improved, but why try again when NSK, Koyo, and NTN are reasonably priced and widely available.
How Can I Be Sure The Wheel Bearing Is Making The Noise I’m Hearing
There are a few other things that can make a noise that sounds very similar to a bad wheel bearing. For instance, if the rear tires become cut due to misalignment and lack of rotation, they will make it running noise that sounds very much like a bad wheel bearing. Another possible cause of a wheel bearing like noise is a failing differential. So, how can you eliminate these as possible causes of your noise?
Accelerate / Decelerate
Acceleration and deceleration changes load on the differential. If there’s a bad bearing in the differential, or wear on the gears, the noise will change pitch slightly as you accelerate and decelerate. Your wheel bearings on the other hand will not change their tone as you accelerate and decelerate.
This test is easy to do. You’ll just need to drive at a speed where the wheel bearings are making noise, usually over 35 miles an hour, and then alternate between stepping on the gas lightly and releasing the gas. Listen for the noise to change.
Swerve Side To Side
Side load will cause a bad wheel bearing’s tone to change. If when you swerve side to side you notice that the noise you’re hearing changes in pitch a little bit, then that is further proof that a wheel bearing is the source of your noise.
Rotate Your Wheels
Check your tires, especially your rear tires, for uneven lumpy wear. Lumpy tires make a noise that sounds very much like worn wheel bearings. You can move the position of the wheels to see if the noise follows the wheels. For instance if you hear what you think might be a wheel bearing noise from the rear, and then find that the rear tires are lumpy, move the rear tires to the front and see if the noise follows.
Raise The Car And Use An Automotive Stethoscope
Wheel bearings don’t really make noise when they’re not loaded, so if you don’t have the weight of the car on the wheels the wheel bearing probably won’t make much noise. However, it may make some, so if you raise the car and spin the wheels you may be able to hear that one wheel sounds different than the others if you place an automotive stethoscope against the knuckle right near the wheel bearing.
Use A Chassis Ear
This is probably the best way to find the source of noises that can only be heard while you are driving the car. A chassis year is a tool that allows you to hook microphones to various areas of the car where you suspect noise may be coming from, and then listen to each of the microphones with a speaker or headphones. Since this tool can be used while driving the car it makes a great for diagnosing wheel bearings.
How to Replace a Wheel Bearing
The first step in replacing a wheel bearing is to remove the brake caliper and rotor, since they are blocking access.
Remove the Knuckle from the Car
Once the brakes are out of the way, we remove the knuckle which contains the wheel bearing. The outer race of the wheel bearing is pressed into the knuckle, so we’ll need to use a hydraulic press to push the bearing out of the knuckle.
Press the Hub Out of the Wheel Bearing
The wheel hub, which is what the wheel mounts to, is pressed into the inner race of the wheel bearing. We use a hydraulic press to remove the hub from the bearing and then we use the press to remove the bearing from the knuckle.
Often the outboard inner race sticks to the hub snout. This is one of the more annoying parts of the job. It’s nearly impossible to use a puller to remove the race, but there are a couple of techniques that work well. One is to grind the race to weaken it, then use a chisel to crack it. Another method is to heat the race so it expands, then remove it while it’s still hot.
Replace Lug Studs if Needed
Subaru lug studs have some issues, so if any are in bad shape, it’s very easy to replace them while replacing the wheel bearing.
Press a New Wheel Bearing into the Knuckle
We press the new wheel bearing into the knuckle using a suitable adapter. The first time you replace a wheel bearing on a new model, finding a suitable adapter is the most difficult part. Since we only work on Toyota, Honda, Subaru, and Mazda, we have it easier than most shops.
Even though we own several sets of wheel bearing and bushing drivers, there are still many applications where we need to manufacture our own for a perfect fit.
Once we have the wheel bearing in place, we install a retaining clip to hold it in place.
Press the Hub into the Wheel Bearing
The final step in the pressing work is to press the hub into the wheel bearing.
We will reuse a hub if it isn’t damaged. However, if a wheel bearing is left unaddressed for too long, the bearing may seize and the inner race may spin on the hub snout, causing damage to the hub. The only good solution in that case is to replace the hub.
Wheel Bearing Replacement Pitfalls
Wheel Bearing Replacement and Rust
Rust makes wheel bearing replacement much more difficult. Sometimes bolts snap off. We’ve had knuckles snap in half rather the disgorging the wheel bearing, even after heat, oil, and lots of beating.
This picture is a Toyota with an aluminum knuckle. The combination of aluminum oxide and rust made it especially difficult to remove the wheel bearing and hub assembly.
Dealing with Stuck Rusty Parts Takes Time
Just removing the bearing from the knuckle, which is normally a 1 minute process, took over an hour of heating and slide hammering.
We removed the layer of aluminum oxide so we could install the new bearing and hub assembly.
In the End, We Usually Succeed
When rust is an issue we have to weigh the cost of all of the different options. For instance, if we could purchase a used knuckle for $100, it wouldn’t make sense to spend an hour trying to save the old one. In this case the knuckle was expensive and would take 3 days to arrive, so the choice was easy, and it all worked out in the end.
In Berkeley? Wheel Bearing Replacement Questions?
If think you may need a replacement wheel bearing and you’re in or around Berkeley, please give us a call. Typically we can determine whether you have a wheel bearing issue with a quick test drive as long as traffic isn’t too bad. Determining which wheel bearing is a little trickier, and we may need to rack the car or use a Chassis Ear to find the faulty wheel bearing. It’s not uncommon for Subaru vehicles to have more than one wheel bearing making noise.