How to Prevent Wheel Bearing Failure

What Are Wheel Bearings?

Wheel bearings are precision-engineered steel balls or rollers enclosed in a race (a metal ring) that sit within the wheel hub.

What they do: To reduce friction between the axle shaft and the wheel hub as your wheels rotate at high speeds. They carry enormous loads, especially on heavy-duty vehicles, and must withstand extreme temperatures, contamination, and vibration.

A failed bearing doesn’t just wear out—it often melts, welds itself to the spindle, or fractures entirely. The result is excessive downtime and costly repairs.

Common Causes of Wheel Bearing Failure

1. Lack of Lubrication

Without grease, friction increases exponentially, leading to overheating. Bearing grease should be high-temperature rated and water-resistant to ensure performance under all conditions.

Dry bearings often screech before they seize—so if you hear metal-on-metal noises from the wheel area, consider it a serious warning sign.

2. Contamination

Dirt, water, or road salt getting into the bearing grease spells disaster. Contaminants act as abrasives, wearing down the races and rollers prematurely. Often, contamination enters through worn seals or during improper installation. Once inside, the grease turns milky or gritty—both signs of impending failure.

3. Overloading

Exceeding the axle rating or loading unevenly puts excess stress on the outer wheel bearings, causing early fatigue. This is common in improperly loaded trailers or when fleet operators push vehicle capacity beyond safe limits.

4. Improper Installation

Over-torquing or under-torquing the spindle nut can quickly destroy a bearing. Excess preload causes heat and accelerated wear; too little leaves the bearing loose, increasing shock load and risk of failure. Even something as simple as failing to seat the bearing properly during maintenance can result in major consequences down the road.

Signs of Impending Bearing Failure

Heavy-duty truck operators and technicians should never ignore the following warning signs:

• Screeching, grinding, or howling noises
• Wheel wobble or looseness
• Overheating hubs or smoke
• Uneven tire wear
• ABS fault codes (caused by excess play in the hub)

A visual inspection during a DOT inspection or preventive maintenance service can catch early bearing issues before they cause road failures.

Preventive Maintenance Strategies

1. Regular Bearing Repacking

Wheel bearings in steer axles should be repacked with fresh grease approximately every 100,000 miles, or sooner if operating in wet or off-road conditions. Use a bearing packer to evenly distribute grease and always replace the seals during this process.

2. Inspect Seals and Races

During PMs or brake jobs, inspect the bearing races for scoring, pitting, or discoloration. These signs indicate overheating or improper torque. Always check the wheel seal for wear or signs of grease leakage.

A leaking seal is often the first visible indication of a failing bearing.

3. Monitor Hub Temperature

Infrared temperature guns can help detect hot hubs before they fail. Routinely checking hub temperatures during walkarounds is a simple way to catch friction build-up early.

Rule of thumb: hubs over 200°F should be investigated immediately.

4. Proper Torque Procedure

When installing bearings, always follow the manufacturer’s torque sequence. Typically, this involves torquing to a higher preload, backing off the nut, and then re-torquing to a lower final value. Using a dial indicator to check endplay ensures precision. Neglecting this step often leads to premature bearing failure—even with new parts installed.

5. Use Quality Parts

Sub-par bearings, low-grade grease, and off-brand seals might save money short-term, but cost a fortune in repairs and downtime. Choose parts that meet OEM specifications for your application. Especially in high-mileage operations, investing in quality components pays off in reliability.

Impact of Bearing Failure on Other Components

When a bearing fails, it’s rarely a stand-alone issue. The heat generated can:

• Warp the brake drum or rotor
• Melt the wheel seal, allowing grease into the brake shoes
• Damage the spindle beyond repair
• Trigger ABS faults

If you suspect a bearing issue, the vehicle should be taken out of service immediately to prevent further component damage or catastrophic failure.

Establishing a PM Schedule

Fleet operators should incorporate bearing inspections into their preventive maintenance and DOT inspection schedules. While not every PM will involve bearing removal, techs should:

• Check for hub oil level or grease leakage
• Spin wheels to listen for abnormal noise
• Wiggle the wheel to check for excessive play
• Use a temperature gun post-trip to monitor for hot spots

Following a documented maintenance schedule not only improves uptime but also demonstrates compliance with DOT and terminal inspection requirements.

Don’t Wait for Bearing Failure

Wheel bearings may be small, but their importance cannot be overstated. By ensuring proper lubrication, monitoring for contamination, avoiding overloading, and following correct installation procedures, fleets can prevent the most common causes of failure.

For operators in Jackson Township, NJ, reach out to our team S&S Fleet Services for all your truck repair needs.