How to Tell if a Trailer's Bearings Are Bad

by Andrew Hazleton
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Trailer bearings are located at each wheel of a trailer, and allow the wheel to spin freely around the axle with minimum friction. All bearings require a constant supply of lubrication, and must be periodically "repacked" with fresh grease to prevent damage. Lack of lubrication can cause a bearing to generate excessive heat. This heat can destroy a bearing, wheel and axle. Grease-based bearing protectors mount over the top of a bearing and provide a constant supply of lubrication.

Check for Noise

Step 1

Locate a deserted stretch of street or parking lot where you can have an assistant safely tow the trailer at a speed of 25 miles per hour.

Step 2

Stand to one side of the road or parking lot.

Step 3

Have your assistant tow the trailer in front of you at a speed of 25 mph.

Step 4

Listen for any squeaks, grinding noises, clicking or any other sound emanating from the trailer wheels.

Repeat Steps 3 and 4 for the opposite side of the trailer. If you hear any noises, the wheel bearing is defective or needs lubrication.

Check for Smooth Motion

Step 1

Place a floor jack underneath a support member of your trailer, and raise one trailer wheel 2 inches off the ground. Secure the trailer with wheel chocks so that it cannot move while it is on the jack.

Step 2

Keep your hand on the wheel and spin it. If you feel any motion that is not smooth, hear any noises, or if the wheel does not spin freely, the wheel bearing is defective or needs lubrication.

Step 3

Grasp the wheel in your hands and attempt to rock it back and forth. There should be a very slight amount of play in the wheel, typically 1/8-inch or less. A lack of play will cause the bearing to heat up. Adjust the bearing retainer nut to add play if necessary.

Repeat with all other wheels of the trailer.

Check for Heat

Step 1

Tow the trailer for a minimum of 10 miles at highway speeds.

Step 2

Stop the vehicle and park in a safe location.

Place your hand on each of the wheel hubs of the trailer. If a hub is too warm to comfortably hold in your hand, the bearing is generating excessive heat and may be defective, have insufficient play or require lubrication.

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