RV Tech Talk

Wheel bearing maintenance

How to inspect, repack and properly care for RV wheel bearings

by Reg DeYoung

The wheel bearings on your RV are a very improtant part of the suspension components. They perform basically two functions: to support the trailer’s loaded weight when it is parked or travelling down the highway and to allow the trailer to make sharp turns. They will also allow the wheels to turn with the least amount of friction.

Today’s wheel bearings are not much different than those manufactured many years ago. They use grease as a lubricant and a heat transfer agent, but the greases available now have changed with the introduction of synthetic products; these offer a more advanced bearing protection.

The bearings used on RVs are known as tapered bearings (see photo at left). They are able to support a greater load capacity due to the increased area within the bearing itself. As well, the cone—shaped rollers will handle axial/side loads much better. These bearings are manufactured with high quality steel that has been case—hardened to increase their durability and further withstand the forces of heat, torque and wear.

The most common types of bearing damage are caused by insufficient maintainance, mishandling, improper installation and adjustment as well as inadequate lubrication. All of which could lead to serious implications—if the bearing is totally destroyed you could lose a wheel or if there is a substantial heat buildup there is the possibility of a fire.

Although the periodic maintainance schedules differ from each trailer manufacturer, you should inspect and repack the bearings every year at the beginning of your RV season, especially, if your trips are usually high—mileage excursions. Even if your RV has been in storage over the winter months, the condensation could have deteriorated the grease and rust may have formed. If you have purchased a used RV and are not aware of the last time the bearings were repacked, it would be beneficial to do this preventive maintainance procedure before you go on your first trip.

The costs and labour times are minimal—whether you do it yourself or have an RV service centre do the work. In most cases, there will be a special set rate that will include parts and labour. An RV technician may find additional problems similar to those that we recently discovered at our shop. When we removed the hub off a customer’s RV, we could see that the brake assembly was installed upside down.

If you decide to repack the bearings yourself, there are a couple of very important safety precautions to keep in mind. Firstly, make sure your coach is properly secured with quality jack stands rated for the weight of your coach. And secondly, never spin a bearing with compressed air—serious injury could occur if the rollers separate from the cage assembly.

The condition of the bearing when removed and cleaned can display many signs of possible problems or probable failure. If there is pitting, scoring or discolouration due to heat damage, you must change the bearing and race as a set. The procedures for removing and installing the bearing race may require a little more effort, experience and the use of tools made specifically for this task. The project is always completed with new bearing seals, cotter pins and, in some cases, new bearing caps. Even though your wheel bearings have been packed recently, you should check them occasionally while travelling for signs of abnormal heat around the centre of the wheel. (I have seen the plastic lug covers melted from extreme heat in this area.) You can also walk along the trailer while your driver moves slowly through a parking lot or campground and if you hear a rumbling or squealing noise you should have the hub assembly inspected as soon as possible.

If you travel for extended periods of time, it’s a good idea to carry a complete bearing set—including bearing seal, washer, nut, cotter pin, cap and enough grease to do at least one wheel hub. At the very least, have the part numbers readily available for the bearings, seals, etc. This will prevent less time downtown and leave more time to see the sights and have fun on your well-deserved vacation.

• Send to a friend
• Comment