Troubleshooting Trailer Hubs That Show Different Operating Temperatures

Question:

I measured about 200 degrees with an infrared thermometer on one side, about 90 on the other.

asked by: Russ

Expert Reply:

The fact that your two brake drums are operating at such different temperatures tells us that at least one of them is having a problem. The 200-degree heat you measured on one of the drums on the trailer axle could be related to the brake assembly being either damaged or misadjusted; or it could indicate a problem with the bearings in that hub. High heat can indicate either inadequate lubrication in the hubs or damaged bearings, which tend to run hotter as they age and wear out.

If the cooler-running hub's brake is not functioning, or is not adjusted properly, this would put the braking burden entirely on the other hub, which would naturally increase its operating temperature.

You'll want to test both brake assemblies to ensure both are operating and adjusted properly. A properly adjusted drum brake will have some slight drag on it, that you can feel and hear as you rotate it by hand, even when the brakes are not applied. I have linked a helpful article that details testing procedures for electric drum brakes.

If you find no functionality/adjustment issues in the brakes then I would next pull the hub that runs hot and check its bearings. Inspect the bearings and spindle surface for signs of discoloration or scoring. I linked two article on how to inspect and re-pack bearings. I also linked our main page for bearings to help you in the event you need replacements.

expert reply by: Adam R