ConMet
A Quarterly Publication of Consolidated Metco, Inc. Summer 2010 - Volume 8
Periodic Inspection for Trailer Hubs Lubricated With Semi-fluid Grease
Figure 1: Note the lubricant on the brake linings.

Driver pre-trip and scheduled maintenance inspections for trailer wheel ends lubricated with semi-fluid grease should be conducted just like those for oil lubricated wheel ends. Due to the consistency of the semi-fluid grease, seal leaks are not as obvious as a leaking wheel seal on a wheel end lubricated with oil. Leaking semi-fluid grease often accumulates on the inside of the brake shoes and is not as readily visible as an oil leak. During all visual inspections, pay special attention to the face of the seal and the inside of the brake shoes to verify that there is not a seal leak (see Figures 1 and 2).

Figure 2: Check the face of the seal for leaks.

Trailer hubs lubricated with semi-fluid grease typically use a hub cap without a sight glass or inspection window. For this reason, as a part of the annual or 100,000 mile inspection, it is important that the hub cap be removed and the lubricant be visually inspected. The visual inspection should verify that the lubricant has not become contaminated and that the volume and consistency of the lubricant are correct.

Additional service information is available at www.conmet.com or by calling ConMet Customer Service at 800-547-9473.


Note in Figure 3 that the ends of the bearing rollers are not covered with lubricant. Additional lubricant should be added through the fill plug in the barrel of the hub until the lubricant flows through the ends of the bearing rollers.



Note in Figure 4 that the lubricant in this wheel end has begun to dry out and no longer flows like semi-fluid grease typically does. This wheel end should be disassembled, cleaned, inspected and refilled with new lubricant. Worn or damaged components should be replaced. The seal should be replaced anytime a hub is removed from the spindle.
Questions about semi-fluid grease should be referred to the lubricant manufacturer. Lubricant analysis should be done anytime there is a question about a lubricant being suitable for use.
End play on the wheel end should also be checked as a part of the annual or 100,000 mile inspection. At five years or 500,000 miles or the second brake job (which comes first), all wheel ends should be disassembled, cleaned and inspected. Any worn or damaged components should be replaced and the hub should be reassembled with a new wheel seal.
Any time a wheel end inspection is done, the hub should rotate freely and smoothly. If there are signs of noise, vibration or rough bearings, the wheel end should be disassembled for inspection.
� Consolidated Metco, Inc.