Sunday Review: No, you don't need to repack your wheel bearings every year.

Notice: I had been doing additional reading and research well after writing this, as well as talked to some more people (these posts are usually written beforehand and then scheduled to be released). This is a very "backyard mechanic" method of maintenance. It does work, but with big caveats. If your hub rear seal is going or you pump the grease in too hard (more likely with an electric or pneumatic pump), you can blow out the rear seal and get grease on your brakes. This will ruin your brakes. If at all possible it is always best to do a full inspection on your trailer's hub and brakes with regularity, which means pulling everything apart (future post). If you have a method of tracking your trailer's mileage, it still needs to have the bearings repacked on the recommended schedule. It is especially true that a new RV should be checked properly after the first year in case of manufacturing defects (Chinesium axles), and a used RV from a private sale should be checked right away. This is all information only, based on what has worked for me. You could damage your RV if something goes wrong, and this summer I am fully pulling apart my wheel assemblies to check brake pads and replace seals. I used this method due to a difficult situation and may never use it again.

Once or twice a decade at most. (Addendum: Depending on how far you go with your trailer each year.)

How often do you get your wheel bearings repacked on your vehicle? Never, you say? Yeah, no doy.

Okay, some of you will have repacked your wheel bearings on your vehicle, but it isn't common anymore and usually you just end up buying new wheel bearings (or replacing entire knuckles). Well, the trailer is only mildly different. (Another addendum: more than mildly, they are designed differently.)


RV and trailer dealers make up a lot of stuff in an effort to get you back for maintenance services and make a quick buck. Notice that they recommend the service. They don't tell you that this is part of regular maintenance. Because it isn't.

The sad fact of the matter is that just like all too many auto shops (blinker fluid isn't real), many RV shops (which face far less competition) are just trying to make money. Sadly, tricking you into buying overpriced services that you don't need earns them more money than being honest.

You only need a few tools for doing wheel bearing maintenance yourself: a flat-head screwdriver, a jack, jackstand, a grease gun and high temperature (or heavy duty) grease (2 or 3 tubes), blue shop towels, a lug wrench or breaker bar, torque wrench, and an appropriate socket.

I already did this all and forgot to take pictures, but I'll show you the pertinent parts and describe the procedure. If anything is unclear, Google it.

Most trailers have a grease fitting for maintenance. Also known as a zerk fitting, zerk nipple, grease nipple, and probably many other names. I've heard that some don't, so grab a flat-head screwdriver and take a look before buying the other tools.

That is just a cap. Use a small flat-head screwdriver to pry it off.

Like so.

Inside that is a rubber dust cover.

Pry this out with your flat-head as well.

Nipple.

There is your grease fitting. If there is no grease fitting, then you really do need to pull everything and repack your wheel bearings. However, most trailer maintenance guides only recommend this every 12,000 miles or 20,000 kilometres - check your maintenance manual. There is no need to do it yearly, though you should still be opening everything to check for damage. Even still, you can do this entirely by yourself at home. Google how, instructions are available.

If you do have the grease fitting, though, you're in luck.

Get together the tools you need. Check your maintenance information (or use Google) to find the recommended torque rating for your wheel nuts - you should be torquing your wheel nuts regularly, so there's limited excuse not to know this information or at least have an idea of what it is supposed to be. Mine is 120 ft-lbs.

Jack up one wheel at a time. Use the U-bolt so that you don't damage anything.

That bolt.

Precautions: Chock your wheels so that the trailer doesn't roll. Use a jack stand to hold up the axle (at the U-bolt), not your jack. Alternatively (NOT RECOMMENDED - DO THIS AT YOUR OWN RISK), use the jack and blocks of wood simultaneously so that both are taking weight.

Remove your wheel. Remove the dust cap. Using your grease gun, force grease into the fitting; it'll take a fair number of pumps. After some pumps, grease will begin to be forced out right before your eyes. Some of it will be dirty. Keep going. Pump until about 1 to 2 inches of grease have been forced out of the bearing or until the grease runs clean. Use a shop towel to clean up the grease that has been forced out.

Done.

Yup. Done.

Put your wheel back together and follow the torque instructions. If you are using a torque wrench, this means tightening up the lug nuts and seating the rim (the rim shouldn't be loose at all), lowering it back to the ground, then following a progressive tightening sequence as described in your maintenance guide. If you have an impact gun and torque sticks, loosely tighten the nuts so that the rim seats, hammer all the nuts on (star pattern, but you should know that), lower the wheel, then hammer all the nuts again.

You only need to do this about once per year, especially if you are torquing your lug nuts regularly.

Keep in mind that this doesn't allow you to check your brake pads, which wear down over time. This isn't particularly difficult to do by yourself, either, but that's for another post (and I'll provide full picture instructions).

WARNING: Mixing different greases can have disastrous results. Do not mix a heavy duty grease with a general purpose grease, for instance. Doing so can cause a chemical reaction that creates a cement-like substance. This WILL destroy your bearings! Repack the bearings yourself so that you know what kind of grease is in the bearing.