You already know that a car cannot be driven properly without a good set of sturdy wheels. What you might not know is that the wheel of a vehicle is not just a simple component and comprises several integrated parts, like wheel bearings, hubs, wheel studs, dust caps, ABS sensors, etc. All these parts work together harmoniously and are subjected to regular abuse, causing them to wear out and eventually fail.
If your vehicle is showing symptoms of a bad wheel hub assembly and you suspect it needs to be replaced, it’s necessary to check if it is the cause of the problem. A cyclic chirping noise is typically a sound caused by a bad wheel bearing. However, bad wheel alignment, worn-out bushings, and brake pads can also lead to this issue. Therefore, it is important to learn how to diagnose a bad wheel hub assembly so you can pinpoint the cause of the problem.
In this article:
1. What Is A Wheel Hub Assembly?
2. How to Diagnose A Damaged Wheel Hub Assembly?
- Inspect For Play
- Roughness Check
- Listen For Any Noise
- Inspect The Wheel Hub Assembly For Run-out
- Monitor For Excessive Heat
3. What Causes A Wheel Hub Assembly To Go Bad?
4. Should You Drive With A Damaged Wheel Hub Assembly?
5. Tips To Maintain And Take Care Of Your Wheel Hub Assembly
6. Should I Replace The Entire Wheel Hub Assembly Or Just The Bearing?
1 What Is A Wheel Hub Assembly?
A wheel hub is an important part of a vehicle that bears the load of the vehicle. The wheel hub connects the wheels at one end and the drive shaft or CV axle shaft at the other. It transfers power from the CV shaft to the wheels. It usually has 4 or 5 long studs to mount the wheels with the help of lug nuts. The vehicle’s brakes are also connected to the wheel hub assembly.
The wheel hub houses precision bearings, seals, Anti-Lock Braking System (ABS) sensors, Traction Control System (TCS) sensors, and wheel speed sensors. The speed sensors constantly relay the speed to the vehicle’s ABS control module. This system uses this information to engage the ABS during hard braking and prevents the vehicle from skidding. The traction control system also uses this ABS sensor to offer optimum traction while driving.
2 How to Diagnose A Damaged Wheel Hub Assembly?
A worn-out or failing wheel hub assembly will show symptoms like roaring or clicking sounds from the wheel, a vibrating steering wheel, abnormal side pulling of the vehicle, and uneven brake pad or rotor wear. If you notice these symptoms, it is time to check your wheel hub assembly to ensure your vehicle functions properly and your safety, as well. Here is a step-wise guide that will help you diagnose your wheel hub assembly.
Inspect For Play
You can check for a bad wheel hub assembly by looking for noticeable play in the wheel using just your hands. You can easily inspect this by following these steps.
- Lift the car using a jack and jack stand and secure the front or rear wheel (whichever is on the ground) using wheel chocks.
- Grab the wheel with both hands at the 12 o’clock and the 6 o’clock positions.
- Gently rock the wheel back and forth to see if there’s any play or slack.
A little or no play is considered good for a wheel hub assembly. Sometimes, when your wheel hub is in the early stages of damage, there are chances it will show little or no play. If you notice a significant play and can hear the wheel bearings clunk and make noise, replace your wheel hub assembly.
Roughness Check
If there is no play in the bearing after checking in Step 1, the bearings inside the hub assembly could be worn and damaged with no play. In such a condition, the car creates a growling noise and produces excessive heat while driving. Here is how to check your wheel hub assembly for roughness:
- Jack up the vehicle and secure it using jack stands.
- Rotate both the adjacent wheels at the same time and check which one stops earlier and makes noise.
- Remove the wheel from the hub. Remove one slide pin and tilt the brake caliper so that the pads are not dragging on the rotor.
- Spin the hub by hand, and pay attention to any unusual resistance or vibration. Compare the hub with other hubs on the vehicle to spot the spoiled one.
- Repeat the process with all the other wheel hub assemblies on the car.
If the roughness and resistance are felt, the wheel hub assembly must be replaced. Put your hand on the suspension coil spring while rotating the wheel/tire assembly. Extreme vibrations felt through the coil show a worn-out wheel hub assembly.
Listen For Any Noise
A faulty wheel hub can produce a growling noise while your vehicle is moving. You may hear this, but you can’t feel it. Therefore, to perform a thorough diagnosis, you need a hoist. You need to run your vehicle in the air, and this could be dangerous to perform on jack stands because your car can pop off the jack stands. Follow the steps below:
- Raise and support your vehicle on a hoist.
- Start the vehicle and engage the dive at a moderate speed.
- Place your hand on the steering knuckle and feel the vibration and noise. You can also use a mechanical stethoscope to listen to the noise.
- Be careful while performing this, and secure yourself and your tools from moving parts to prevent any accident.
- Compare the noise level from different hubs. The noisier one is possibly the bad one and needs to be replaced.
You can also perform this using an electronic stethoscope, such as the Steelman Pro-65001. These stethoscopes have individual mics that can be placed at each wheel and can pinpoint a faulty wheel hub assembly.
Inspect The Wheel Hub Assembly For Run-out
The lateral movement or amount the hub deviates from the center is referred to as wheel hub runout. A hub runout can cause mild to excessive vibrations either in the steering, the entire vehicle, or the brake pedal. Inspecting runouts is not an everyday exercise, and only a few mechanics perform this method for checking your wheel hub. To perform this inspection, you need a dial indicator. Perform the following steps to inspect for runout:
- Jack up the vehicle and secure it with a jack stand. Secure the wheels on the ground using wheel chocks.
- Remove the wheel and remove the brake caliper and rotors, too.
- Mount the dial on the steering knuckle.
- Place the dial gauge’s tip on the face of the hub and set the dial gauge to 0.050″. Make sure the tip runs on the farthest point from the center of the hub.
- Zero the dial gauge by rotating its face and locking it there.
- Rotate the wheel hub slowly and note down the change in the readings of the dial gauge for the runout. Compare these readings with the manufacturer’s specification for any runout.
The farthest point on the face shows the maximum runout. The maximum allowable runout will depend on manufacturer specifications, so always consult your vehicle’s specifications in the manual. If the runout exceeds the permissible limit, you might have to replace the wheel hub assembly. Refer to our complete wheel hub assembly replacement cost guide.
Monitor For Excessive Heat
Friction in bearings makes them hotter than usual. Lack of lubrication in bearings can cause excessive friction and wear. Although this method is not so accurate, it proves to be helpful while inspecting for a bad wheel hub and bearing. To inspect, you’ll need an infrared thermometer.
- Drive your vehicle to a distance while listening for any noise from your hub bearing.
- After the test drive, park your vehicle and inspect the temperature of the hub with your infrared thermometer.
- If the temperatures of the hub differ, the hotter one is most likely the damaged one.
3 What Causes A Wheel Hub Assembly To Go Bad?
Wheel hubs last a long time, but just like every other part, they wear out because of prolonged usage and exposure to road elements. Three major factors that cause damage to the wheel hub assembly are:
1. Impacts And Accidents
Whenever your vehicle tire hits a pothole, curb, or a large obstacle, there are chances that your wheel bearing gets damaged. The bearing either breaks or becomes weaker, leading to eventual failure. If your car’s handling changes after a hard hit on a pothole or obstacle, it’s time to inspect the wheel hub assembly.
2. Contamination And Lack Of Lubrication
Like every other component under the vehicle body, wheel hubs are also exposed to water, dirt, dust, and other contaminants. This causes vehicle components to corrode over time. Cars in cold climates are subject to road salt, and in rainy areas, water may splash on the components in the undercarriage. These contaminations cause damage to the bearings and increase the friction between the bearing components, ultimately damaging the wheel hub assembly.
3. Improper Alignment
The primary task of a wheel hub assembly is to connect the axle and wheel and allow the wheel to spin smoothly. When your vehicle travels in a straight line, it puts only minimal stress on the wheel bearing. A vehicle with bad alignment pulls your vehicle to one side and requires direction correction every second while driving. In such a situation, you have to keep your steering wheel turned slightly to keep the car going straight. This causes stress in the bearing and leads to reduced wheel bearing life. Ensure your vehicle has proper wheel alignment to prevent such issues.
4 Should You Drive With A Damaged Wheel Hub Assembly?
The wheel hub assembly is a sturdy component that lasts a long time, but sometimes it can wear out earlier than expected. Most drivers will have to deal with a damaged hub assembly in their vehicle’s lifetime. A damaged wheel hub assembly may fail drastically, causing you to lose control of your vehicle and risk your life. It also affects the proper functioning of your car and can increase the wear and tear on other vital components, including your brakes, transmission, axle shaft, and CV joints. In the worst-case scenario, a bad wheel assembly can even break out, detaching your wheel from the vehicle and causing a major accident. Therefore, it is advised not to drive if you have a bad heel hub assembly and to get it diagnosed as soon as possible.
5 Tips To Maintain And Take Care Of Your Wheel Hub Assembly
Proper lubrication keeps your wheel hubs working efficiently for a long time. All you have to do is maintain the lubrication by re-greasing at the recommended intervals, using the right specifications of oils and greases. Routinely check the wheel hub assembly for any signs of leakage caused by damaged seals. Furthermore, the life of your wheel hub depends on your driving habits and road conditions. Harsh and rough driving can also cause your wheel hub assembly to get damaged well before its lifetime. Proper driving habits and moving slowly around bumps and curves reduce the stress on hubs, making them last longer.
6 Should I Replace The Entire Wheel Hub Assembly Or Just The Bearing?
Most of the hub assemblies these days are sealed units and cannot be dismantled without destroying them. But there are hub assemblies that can be dismantled so the bearings can be replaced separately. In either case, it’s always recommended to replace the hubs on both sides at the same time. This not only helps you to improve your vehicle’s ride quality but also saves you time and the money you would have spent on labor. Finally, finding a perfect replacement wheel hub assembly plays a vital role in the performance and life of the component. To understand the types of wheel hub assemblies, refer to our ultimate wheel hub assembly buying guide, which will help you purchase the correct part for your vehicle.
