How to tell if a Subaru wheel bearing is bad?
Short answer: Look for a changing humming or grinding noise, steering vibration or pulling, uneven tire wear, and ABS/traction-control warning lights. If these symptoms appear, the wheel bearing (often part of the hub assembly) is likely failing and should be inspected.
In-depth context: Subaru wheel bearings are typically integrated into the hub assembly, and AWD models place additional load on these components. A failing hub can affect steering response, ride comfort, and safety. This guide lays out the most common signs, how to check them safely, and what to do next if you suspect a bad bearing.
Common signs of a bad wheel bearing
These are the symptoms most Subaru owners report when a wheel bearing starts to fail. Check for one or more of these indicators, especially if they appear together or worsen over time.
- Unusual noise: a low-pitched hum, rumble, or grinding that changes with vehicle speed and with direction of travel (often more noticeable when turning).
- Vibration or steering feedback: noticeable vibration in the steering wheel, seat, or floor at highway speeds, sometimes described as a “wobble” or “gritty” feel.
- Tire wear irregularities: cupping or uneven wear on one edge of a tire that cannot be explained by alignment alone.
- Pulling or drifting: the vehicle tends to pull to one side or the steering feels slightly off-center due to hub imbalance.
- ABS/Traction control warning lights: a failing wheel-speed sensor in the hub can trigger the ABS or traction-control light.
- Hub area heat or smell: after a drive, the hub/nearby area may feel warmer than usual; in some cases you may notice grease on the wheel or brake components.
Concluding: If you notice any of these signs—especially in combination—schedule a professional inspection. Ignoring a bad wheel bearing can lead to further damage or, in worst cases, wheel separation.
How to diagnose safely
Use these checks to narrow down whether the hub bearing is the source of the problem. Some tests require a professional lift and tools.
- Listen for noise across speeds: drive on a smooth surface and note whether the noise changes with speed, road surface, or when cornering. Bearing noise often worsens with speed and during turns.
- With the vehicle raised and the wheel removed, check for play: grasp the wheel at 3 and 9 o’clock and 12 and 6 o’clock positions and gently try to move it. Excessive lateral or vertical play suggests bearing wear or a loose hub.
- Perform a spin test: manually rotate the wheel/hub and listen for grinding, roughness, or binding. A healthy bearing should spin smoothly with the slightest resistance and no noise.
- Check for heat after a short drive: safely inspect the hub area after driving; an abnormally hot hub can indicate a failing bearing.
- Observe the ABS/traction lights: if these lights are illuminated or flashing, a wheel-speed sensor associated with the hub may be affected by a failing bearing.
- Consider professional verification: a shop can measure hub runout with a dial indicator and verify bearing preload; many Subaru models require hub assembly replacement rather than bearing-only service.
Concluding: These tests help distinguish a worn wheel bearing from other issues (like CV joints or suspension components). If you find significant play, roughness, or heat, seek a professional inspection promptly.
What to do next
If the checks point toward a bad bearing, take appropriate safety and repair steps. Here’s how to proceed.
- Avoid driving long distances or at high speeds if you suspect a failing bearing. Have the vehicle inspected as soon as practical to prevent further damage or unsafe driving conditions.
- Expect that many Subaru models require hub assembly replacement (which includes the bearing and sometimes the ABS sensor) rather than a bearing-only fix. This can influence both cost and downtime.
- Obtain a written estimate from a reputable shop, and ask about whether the replacement includes new studs, ABS sensor integration, and wheel alignment checks if needed.
Concluding: Prompt diagnosis and proper replacement reduce the risk of wheel failure, protect AWD drivetrain reliability, and maintain safe handling.
Why Subarus may show wear on wheel bearings
Subaru AWD systems can place additional stress on front hubs, particularly in older models or those with higher mileage and frequent pothole or rough-road exposure. Regular maintenance, careful driving, and timely tire rotations can help extend bearing life. In many models, the hub assembly is a sealed unit, so replacement often means swapping the entire hub rather than replacing individual bearing components.
Summary
Key indicators of a bad Subaru wheel bearing are a changing hum or grind, steering vibration or pulling, uneven tire wear, and ABS/traction-control warning lights. If you notice any of these signs, have the bearing inspected promptly. Diagnosis typically involves listening tests, a physical play check with the wheel elevated, a spin test for roughness, and, if needed, professional runout measurements. Replacement usually involves installing a new hub assembly and can vary in cost depending on model and whether the ABS sensor is integrated. Prioritize safety and seek a trusted technician for confirmation and service.
