In the early operational days of Matchpoint Auto Transport we were replacing trailer brake sets every 3-4 months because our drivers were running with their electronic trailer brake settings too high. We were also getting in trailer tires with flat spots, from excess braking, which is an expensive mistake and a good discussion for another time…
As our drivers “matured” they learned how to better manage trailer brake settings which safely extended brake shoe life. We also switched to the use of self adjusting brake sets. The combination of better brake settings with self adjusting brake extended our trailer brake replacement interval from 3-4 months out to a 6-8 month window… great news right? Not a total win when wheels start falling off your trailer.
We recently inspected a drum and brake set from wheel that fell off one of our trailers. (the subject of part 1 in this series) The brakes looked “OK” after 7 months, probably ready to replace, but far from failing. The bearings were destroyed.
The unexpected benefit from our lousy driver braking management, was that as we were replacing brake sets every 3-4 months, the mechanic was also tightening and sometimes replacing wheel bearings. Basically our brakes needed replacement before our wheel bearings had a chance to fail. As we extended the life of our brake sets with better electronic brake management, we began seeing bearing failures before our brakes needed to be replaced. It’s always something…right? Now our wheel bearings need more attention than our brakes…
As a result of this experience we have developed a 3-point observation strategy to assess the condition of a trailer's wheel bearings. The advantage of these three strategies is that anyone can make the observations and there is no need to remove a wheel, or jack up the trailer. Keeping in mind that Kaufman recommends wheel bearing maintenance every 12,000 miles, here are a couple quick tests the assess the condition of your wheel bearings, healthy wheel bearings, leads to a healthy trailer.
First: The Temperature Test
At just about every fuel stop the driver should do a trailer walk around. This obviously is to re-check the security of the load, look for a low tire, but should also include a quick hand touch to each trailer wheel hub. Even when loaded the hubs should remain comfortable to the touch, if a hub feels warm or even hot, it’s an indication of a problem. The solution could be as simple as a couple good shots of grease, if the hub has a grease fitting. (standard on a Kaufman trailer) We've had numerous situations on the road where a hub feels warm to hot, grease is injected at the fuel stop, and 10 miles down the road running again at a normal temperature.
Second: The Wiggle Test
With the trailer empty, grab both sides of a trailer wheel at 9 and 3 o’clock and try to wiggle the wheel back and forth. There should be zero wiggle in the wheel, even a small amount of detectable wiggle indicates the bearings have loosened.
Third: The Tire Wear Test
Any observation of uneven wear on trailer tires in an indication of a problem. The earlier this is noticed the better. Uneven tire wear can be caused by an axle problem or wheel bearings. When a wheel bearing is breaking down and the wheel starts to torque in or out of alignment the tire on that wheel will wear down quickly on the inside or outside edge.
Using these three tests on a regular or daily basis will give you the opportunity to identify and repair wheel bearing problems early, and prior to a serious failure.