At STEMCO, we have a rich history of manufacturing the best seals, hub caps, bearings, axle fasteners, and king pins in the industry. Nothing is more important to us than having our customers experience the safety, performance, and confidence of having high-quality STEMCO components on their trucks.
This is especially true when it comes to hub caps. The hub cap endures constant physical abuse from the elements and internal factors that can affect its characteristics both visually and functionally. STEMCO hub caps are engineered to keep equipment on the road and keep contamination out of wheel ends.
The purpose of this tech tip is to inform customers of proper lubrication methods for SENTINEL® hub caps with oil, SENTINEL stamped steel, duckbill vented stamped steel, dirt exclusion hub caps with semi-fluid grease, and stamped steel hubcaps with hard pack grease. We will be referencing the following STEMCO PDFs:
Oil Lubricant
SENTINEL Hub Caps
When using oil lubricants, the following procedure should be followed. Adherence to this procedure will result in longer wheel end life and improved performance.
STEP 1
After the hub cap has been installed on the hub, slowly pour oil through the side fill hole. Allow the oil to flow into the hub cavity, and do not fill the oil level past the bottom of the red cover or the red shaded area below. Allow two to three minutes for the oil to migrate into the hub cavity and repeat process as needed until the oil level is at the full line on the clear hub cap window.
- Do not cover the vent mechanism with lubricant.
- Failure to follow the above procedure will result in “filming” or cosmetic seepage of lubricant through the center vent onto the external face of the hub cap during initial operation.
- Do not cover the vent mechanism with lubricant!
- Failure to follow the above procedure will result in “filming” or cosmetic seepage of lubricant from the vent onto the external face of the hub cap during initial operation.
- Do not cover the vent mechanism with lubricant.
- Failure to follow the above procedure will result in “filming” or seepage of lubricant from the vent onto the external face of the hub cap during initial operation, and may clog the vent in some cases.
Semi-Fluid Grease
SENTINEL, Dirt Exclusion, Duckbill Vent, Solid Aluminium Grease Hub Caps
When using semi-fluid lubricants, it is recommended to add lubricant to the hub caps to provide added lubrication to the outer bearing. Adherence to this procedure will result in longer wheel end life and improved performance.
Addition of semi-fluid lubricant should be completed as follows:
STEP 1
Holding the hub cap, fill the lower side of the hub cap until level with the inner edge of the mounting flange and the edge of the vent mechanism.
STEP 2
Install the hub cap quickly to prevent spilling the lubricant.
Hard Pack Grease
Stamped Steel Hub Caps
STEMCO stamped steel hub caps are zinc dichromate plated to provide corrosion protection and a superior finish. While the plating provides ample protection in most instances, there are conditions which can accelerate corrosion beyond the capability of the plating.
For this reason, STEMCO recommends that all stamped steel hub caps be internally coated prior to installation, except for the vent, with a thin layer of lubricant.
Coating should be performed as follows:
STEP 1
Using a clean brush or your hand, wipe the inner surfaces of the stamped hub cap with a thin layer of lubricant until all areas are covered as shown.
STEP 2
For this purpose, NLGI grade 2 or 3 hard pack greases are the preferred lubricants, as they do not flow and will maintain coverage of the plating on the internal surface of the hub cap.
STEP 3
Install the hub cap per normal installation practices.
STEP 4
Use this procedure on all STEMCO stamped steel hub caps.
Lubrication
With the vast array of wheel end configurations and operating variables, STEMCO recommends following manufacturer’s recommendations for lubricant selection.
Additionally, STEMCO endorses The Maintenance Council’s recommended practice RP 631 (Recommendations for Wheel End Lubrication) and RP 624 (Lubricant Fundamentals), available from TMC.
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