Proper Wheel End Service

It’s all about knowing the components and RTB


Installation instructions included with the seal will identify if any surfaces of the seal should be lubricated prior to being installed. The instructions will also identify if special installation tools are needed, along with how they are to be used.

After the seal is installed, caution should be exercised to insure that the seal is not cocked or damaged as the hub is placed on to the spindle. As soon as the hub has been placed on the spindle, it should be supported and the outer bearing should be installed to prevent the seal from becoming cocked.

All seal manufacturers have an approved lubricants list. These lubricants have been tested with their seals to insure there will be no chemical reactions between the seal and the lubricant that would reduce the life of the seal. Only approved lubricants should be used in any wheel end.

In addition to the installation information that comes with the seal, most seal manufactures have product handbooks available that will provide additional information, including information on failure evaluation. While seal leaks are typically the most common type of wheel end maintenance, many seal performance issues can be prevented with the use of the proper installation tools, proper bearing adjustment, and handling procedures.

BEARINGS

Hubs with manually adjusted bearings and PreSet/LMS hub assemblies use tapered roller bearings and are serviceable. Unitized hub assemblies use a cartridge type tapered roller bearing assembly that can not be serviced.

The bearing cones should be washed in petroleum-based solvent prior to inspection. Once the bearings have been cleaned, blow compressed air through the rollers to dry the bearing. Do not spin the bearing with compressed air. The bearing could come apart causing damage or personal injury.

After the bearings have been inspected, if they are suitable to be reused, lubricate them in the same type of lubricant that will be used in the wheel end and store them in oil paper or a clean shop towel until you are ready to reassemble the hub.

Any bearing cup that shows signs of wear or damage should be replaced. If a bearing cone is dropped, it should be replaced. Damage from the impact could have occurred that may not be readily visible but could affect the operation of the bearing.

If the bearings are to be replaced, it will be necessary to remove the bearing cups from the hub. The bearing cups can be pressed out of an iron hub using a press or soft steel punch and a hammer. The bearing bores in an aluminum hub can be damaged if the bearing cups are driven out of the hub with a press or a punch.

To eliminate the chance of damage to the hub, weld a bead around the face of the bearing cup. Turn the hub over and allow the weld to cool.
As the weld cools, the bearing cup will shrink and will often slide out of the bearing bore. After the weld has cooled, if necessary, use a soft steel punch and a hammer to remove the cup from the bearing bore.

Once the bearing cups have been removed from the hub, clean the hub to remove old lubricant or foreign material that may be present. Once the hub is cleaned, inspect it for damage and then inspect the bearing and seal bores for signs of nicks, gouges or scratches. Use emery cloth to remove any surface imperfections that may be in the bearing or seal bores, or on the bearing cup seat. If the bores are scored or damaged, the hub should be replaced.

To install the new bearing cup in an iron hub, use the appropriate driver to prevent damage to the bearing cup. Verify the cup is pressed against bearing cup seat of the bore by using a 0.002-inch feeler gage to insure the cup is seated correctly.

To prevent damage to the bearing bore when installing the bearing cup in an aluminum hub, the hub should be heated using boiling water or an oven. Never attempt to heat the hub with a torch.

The bearing cup may also be chilled to aid in assembly. Heat the hub to 212 °F to 300 °F. Higher temperatures will make installation easier, but exceeding 300 °F will weaken the hub by destroying the heat treatment applied at time of manufacturing. Use the appropriate cup drive as necessary to seat the bearing cup. Once again, verify that the cup is pressed against the bearing cup seat of bore by using a 0.002-inch feeler gage to insure the cup is seated correctly.

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