Equipment Inspections - Trailer Wheel Ends

There are two basic kinds of wheel hubs that you’ll find on a trailer.

1. Sealed Grease Hubs
     The hubs pictured below are packed in grease and are intended to be long life, maintenance free, and non-serviceable. From a drivers stand point, there is nothing to check when doing your pre and post trip inspections. Grease hubs are obvious to spot because they have no filler plug for adding oil, and they usually have a plastic or steel cap covering the end of the axle.



2. Oil Bath Hubs

     Oil bath hubs require regular service and inspection. As a driver you should be checking the oil level of each trailer hub at your pre-trip inspection, as well as ensuring that there is no evidence of oil leakage. Oil will typically leak from two places, either from the hub cap itself on the outside of the wheel, or from the seal at the back side where the hub meets the axle. In either case, if the oil leak becomes severe enough the hub will eventually lose all of its oil. Loss of oil will have the affect of burning out the wheel bearing inside the hub and could lead to a fire or even worse, wheel loss.

Oil Bath Cap

Oil Bath Cap with a Hub-odometer - Oil should be filled to roughly the 4 or 8 o’clock level.

Close up of Oil Level - Oil should be between the add and full marks, slightly overfull isn’t really an issue as long as it isn’t leaking.

     An example where oil is leaking onto the rim from the hub cap. This is a defect that should be reported and fixed as soon you return to the yard, or sooner if the leak is severe enough. In this example, you can see that there was no panic because the oil level was still close to the full mark, as seen in the sight glass.

Disclaimer: K.A.M. makes no guarantees regarding the accuracy of this information. It is intended for educational and assistance purposes for the drivers of K.A.M. Trucking Inc.