Brian Beathard

You have tried every type of seal. You have completed text-book bearing adjustments. You have ensured all components were clean, in good working order, and properly lubed. Still, one wheel end keeps having issues with leaky seals. I get this call often. I can always feel the frustration of the person on the other end who has seemingly done everything right on four separate wheel positions—and one wheel end keeps having seal issues.

When it comes to the wheel end (as with most things in life) it is often what we cannot see that ultimately gets us in the end. After all, you cannot fix what you do not know is broken. Spindles, like all components, wear over time. Most of the wear on a spindle occurs underneath, where it is difficult to see. And the amount of wear required to cause seal issues can be negligible to say the least. This wear generally comes from age, but can be accelerated by poor bearing adjustments, extreme heavy loads, or misalignment.  The issue is known as “fretting”; and it can cause a perfectly round spindle to begin to resemble the letter “D”.

To determine if this is what is causing your wheel seal woes, use a caliper, and measure the spindle at the 12:00 and 6:00 o’clock position. Then take a separate measurement at the 9:00 and 3:00 o’clock position. I generally recommend taking the measurement further back on the spindle where it meets the spindle shoulder (see picture). Bottom line, if the difference between the two measurements is greater than 6-thousandths, you have found your issue. In extreme cases, you can reach underneath and actually feel the flat spot.

This issue may actually be a good thing:As frustrated as you are over the problem and the cost associated with fixing the problem, discovering the issue now, by way of leaky seals, has likely saved you a greater heartache and expense. If allowed to persist, through short term remedies such as frequent bearing adjustments or masking with hard pack grease, you could end up with the coup de graceof wheel end problems—a wheel off.  Repair the situation by either purchasing a new axle or calling an Axle Surgeon out to replace the spindle.

Brian Beathard is a Wheel End Specialist with RevHD, LLC. He can be reached at (844) REV-SEAL.