What a wheel hub assembly does and when it needs replacing
A wheel hub assembly is the part that connects your wheel to your car's suspension and brake system. It holds the wheel bearing, which lets your wheel spin smoothly, and it bolts to your brake rotor and suspension. When a hub assembly fails, you'll usually notice a grinding or humming noise that gets louder as you turn, or your wheel may feel loose or wobbly.
You need to replace it when the bearing inside wears out or the assembly itself cracks. A bad hub assembly can damage your brakes and suspension if you keep driving on it, so this is not a repair to delay. The job takes 1 to 3 hours per wheel depending on your vehicle and how stuck the bolts are.
Key Takeaways
- A wheel hub assembly connects your wheel to the suspension and holds the wheel bearing; it fails when the bearing wears out or the assembly cracks.
- You will need a jack, jack stands, a socket set, a hub puller tool (usually rented), and new bolts, because the old ones often cannot be reused safely.
- The hardest part is usually removing the old hub because the bolts corrode and seize; soaking them in penetrating oil the night before saves time and frustration.
- If the bolts will not budge after soaking, or if you do not have a safe place to work, a shop can do this job for $300 to $800 per wheel depending on your vehicle.
Tools and parts you will need
Before you start, gather the right tools. You need a floor jack and at least two jack stands rated for your vehicle's weight. You also need a socket set with the correct size sockets for your vehicle's hub bolts (usually 17mm, 19mm, or 21mm), a breaker bar or ratchet wrench, and a hub puller — a three-legged tool that pulls the old hub straight off the spindle. Most auto parts stores rent hub pullers for $20 to $40 per day.
Buy a new hub assembly for your specific vehicle make, model, and year. You also need new bolts; the old ones stretch when you tighten them and lose their grip, so reusing them risks the wheel coming loose. Some shops include new bolts with the hub, but check before you buy. You may also need a new brake rotor if the old one is warped or scored, and new brake pads if you are doing the work anyway.
Have penetrating oil (like PB Blaster or Liquid Wrench) on hand. Spray the hub bolts the night before you work so they loosen more easily. A wire brush or wire wheel on a drill helps clean corrosion off the spindle after you remove the old hub.
Removing the wheel and brake components
Loosen the lug nuts on the wheel while the car is still on the ground — they are much harder to turn once the wheel is in the air. Then raise the vehicle with the floor jack and find it on jack stands. Never work under a car supported only by a jack.
Remove the lug nuts and take off the wheel. You will now see the brake caliper bolted to the hub assembly. Unbolt the caliper (usually two bolts) and hang it from the suspension with a wire or bungee cord so it does not hang by the brake hose. Remove the brake rotor by unbolting it or sliding it straight off the hub, depending on your vehicle's design.
Look at the back of the hub assembly. You will see a center bolt or nut holding the hub to the spindle, and several bolts around the edge holding the hub to the suspension. Spray all of these with penetrating oil and let it soak for at least 30 minutes, longer if the bolts look heavily corroded.
Separating the old hub from the spindle
The center bolt or nut that holds the hub to the spindle is often the tightest fastener on the job. Use your breaker bar and the correct socket size — do not use an adjustable wrench, which will round off the corners. If the bolt will not turn after soaking, spray it again and wait another 15 minutes. Tapping it gently with a hammer sometimes helps break the corrosion seal.
Once the center bolt is out, use the hub puller. Thread its three legs into the threaded holes on the back of the hub assembly (or bolt them to the hub if there are no threads). Tighten the center screw of the puller slowly and evenly. The hub will slide straight off the spindle. Do not try to pry it off with a screwdriver or hammer — you will damage the spindle and the new hub will not fit.
Cleaning the spindle and installing the new hub
Once the old hub is off, clean the spindle with a wire brush or wire wheel. Remove all rust, corrosion, and old brake dust. The spindle surface must be smooth and clean so the new hub sits flat and the bolts tighten evenly. Wipe it down with a clean rag.
Slide the new hub assembly onto the spindle. It should slide on smoothly without forcing. If it does not, stop and check that the spindle is clean and that you have the correct hub for your vehicle. Install the new center bolt or nut and tighten it by hand first, then use your socket and breaker bar to tighten it firmly. Do not overtighten — the bolt should be snug, not stripped.
Now bolt the hub to the suspension using the new bolts you bought. Tighten these bolts in a star or cross pattern (like tightening lug nuts) so the hub sits evenly. Tighten them firmly but do not strip them. If your vehicle's manual gives a torque specification, use a torque wrench to tighten to that value.
Reinstalling brakes and the wheel
Install the new or cleaned brake rotor onto the hub. Bolt it in place if your vehicle requires it. Slide the brake caliper back over the rotor and bolt it to the hub using the original bolts. Make sure the caliper is centered on the rotor and does not rub.
Put the wheel back on and hand-tighten the lug nuts. Lower the vehicle to the ground with the jack. Once the wheel is on the ground, tighten the lug nuts in a star pattern with your socket wrench. Tighten them firmly so the wheel cannot slip, but do not overtighten — you can crack the rotor or strip the studs.
Repeat this process for the other side if you are replacing both hubs. After you finish, drive slowly for the first 10 miles to make sure the brakes feel normal and the wheel does not make noise. If you hear grinding or the wheel feels loose, stop and check your work.
When to call a professional instead
If the hub bolts will not loosen after soaking overnight, or if you do not have a safe place to work with jack stands, take the vehicle to a shop. Stripping a bolt or damaging the spindle will cost more to fix than paying a shop to do the job right the first time. A professional mechanic can usually replace a hub assembly in 1 to 2 hours and will have the right tools and experience to handle stuck bolts.
If your vehicle has an electronic parking brake or integrated wheel speed sensors in the hub, a shop may be the better choice. Some newer vehicles require reprogramming after a hub replacement, and a shop has the diagnostic equipment to do that. The cost for a shop to replace one hub assembly usually runs $300 to $800 depending on your vehicle and whether new brakes are needed.
Frequently Asked Questions
Can I replace just the bearing inside the hub, or do I have to replace the whole assembly?
Most modern hubs are sealed units where the bearing cannot be replaced separately. You have to replace the entire assembly. Older vehicles sometimes had replaceable bearings, but even then, if the bearing is bad, the hub itself is usually worn and should be replaced too.
Do I need to replace both hubs at the same time?
No, you only need to replace the one that is bad. However, if both hubs are old and one is failing, the other may not be far behind. Ask a mechanic to inspect both sides and replace whichever ones are worn.
What if my vehicle has all-wheel drive?
The process is the same, but you may need to disconnect the axle shaft from the hub before you can remove it. Check your vehicle's service manual for the exact steps. Some all-wheel-drive vehicles also require you to support the axle with a jack while you work so it does not hang and damage the transmission.
How long does a new hub assembly last?
A quality hub assembly usually lasts 100,000 to 150,000 miles or more if your vehicle is well-maintained. Rough roads, potholes, and hard cornering can wear a hub faster. If you replace it with an OEM (original equipment manufacturer) part rather than an aftermarket part, it typically lasts longer.
Do I need to bleed the brakes after replacing the hub?
No. Replacing the hub does not open the brake system, so you do not need to bleed the brakes. However, if you removed the brake caliper, make sure it is bolted back securely and that the brake hose is not kinked or pinched.