Trailer Wheel Bearings: RV Maintenance and Repair Tips

Your trailer's wheel bearings play a vital role in supporting the trailer's weight and allowing the wheels to spin without putting excessive stress on the trailer axle. The number one reason for wheel bearing failure is due to improper maintenance, which means your RV trailer bearings must be inspected or replaced according to the service intervals established by the manufacturer.

Improper maintenance of your wheel bearings isn’t just a risk to yourself; not properly servicing your wheel bearings can compromise the safety of the passengers in the tow vehicle and those that share the road with you. Failure to maintain axle bearings can cause your wheels to fall off while the trailer is in motion.

Yikes!

To avoid such wheel bearing hazards, follow these important steps for maintenance and repair:

• Refer to your RV owner’s manual to determine when your wheel bearings should be serviced. As a rule of thumb, most RV owners should inspect and grease wheel bearings at least every 10,000 miles.


• Safety first! Use the proper lifting equipment/jack for the task at hand by verifying you are using the proper “weight” rated jack stands. Beyond making sure you have the right tools; the most important safety equipment you can get are safety glasses and hand protection/gloves. Of course, dress appropriately and remove all jewelry.


• Check the owner’s manual for the proper torque values for the wheel bearings and wheel lug nuts. Wheel lug nuts will become loose over a period of time so it’s vital to verify proper wheel lug nut torque even before a wheel bearing service is performed.


• Obtain a proper trailer jack and block all tires on the opposite side with wheel to ensure your safety while servicing the trailer.


• Remove the wheel, center cap from wheel hub and cotter pin from axle nut (the axle nut will have “six” notches that line up with cotter pin hole in the axle/spindle). Then remove the “flat” thrust washer and outer hub bearing.


• Keep all the parts you just removed in the order that they were removed and place the removed parts in a suitable container to keep out dirt or debris.


• Firmly pull on the wheel hub to remove from axle.


• Use a proper wheel bearing seal remover to remove the seal from the outside/brake side of the wheel hub. You can then discard the wheel bearing seal because you will be installing a new seal during reassembly. Remove inner wheel hub bearing (protect this bearing from dirt/debris also).


• With proper wheel grease (not all axle grease is compatible with other types of axle grease), repack both the inner and outer wheel hub bearings. If you do not have a wheel bearing packer you can use hands to work in the new grease; a technique called ‘packing the wheel bearings.’


• Place the wheel hub on a flat surface with the inner wheel bearing facing you and install the freshly packed inner wheel hub bearing.


• Then replace the inner wheel bearing's old grease seal with the new seal. Turn the new grease seal (the biggest, flattest part) facing you and use the proper seal driver to install the seal. Apply a light coating of grease to the lip of the seal.


• Install the assembled hub back onto the axle/spindle and then put in the outer bearing, the flat washer and finally the axle nut. Follow the proper axle nut torque procedures in your owner’s manual.


• Now install the castellated tab that goes over the axle nut. Align the castellated nut cover with the cotter pin hole in the axle, and then install the new cotter pin and outer grease cap.


• Now adjust the trailer wheel brake. A slot in the rear of the brake drum will provide access to a star wheel for adjusting the brake's friction. The star wheel won't be visible as it’s hidden inside the drum, but it looks like a small bicycle sprocket.


• Remove the plug from the slot and insert a flat-head screwdriver to turn the star wheel. Adjust the tension until the wheel will no longer spin and then back off your turn one notch at a time until the wheel is spinning with minimal drag.


• Reinstall wheel/tire and torque wheel to specs and you’re done!

If you have any doubts in your ability to perform the required service, consult a qualified repair shop in your area. With a Good Sam Roadside Assistance plan, Good Sam can help you find a qualified mechanic in the vicinity.

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Photo: Bill & Vicky Tracey