It’s not a job for everyone, but knowing how to repack trailer bearings can save you money and a roadside repair. Get out your gloves and coveralls, and let’s look at the dirty job of repacking trailer bearings.
Most modern RVs have easy lube wheel bearings, making the job of repacking wheel bearings much easier. This style of wheel bearing can be greased, pushing out old grease for fresh stuff without even removing the wheel.
Previous to the easy or quick lube bearings, wheel bearings were a little more work to service. Some RVs still use wheel bearings, which require repacking, and if you have an older RV, your bearings most likely need to be repacked.
When and Why To Repack Trailer Bearings
Wheel bearings on trailers serve a very important job in allowing the axles to spin freely. These bearings are spinning at high speeds and are under load from the weight of your RV.
This combination of load and high speed creates heat, making the job even more difficult. Add in road grim and wet weather, and your wheel bearings have a lot to contend with. Grease is used to assist bearings to spin freely and protect them from all the challenges they have to withstand.
Repacking trailer bearings with fresh grease is critical to the operation and life of the bearings. How often you repack bearings will be dependent on how much traveling you do. Before the beginning of each season is the best time to do a repack, and this one repack is enough for those not putting on many miles.
If you are a road warrior, more frequent service will be required. 10,000 miles is the most commonly agreed-upon number for those who put on more miles. This may be 2 or 3 times a year for higher mileage trailers which seems inconvenient, however not as inconvenient as changing a wheel bearing on the side of the highway!
Overheating wheel bearings can actually start fires, and this has happened to RVers. Checking your wheel bearing temp either with a temperature gun or simply by touching the wheel during fill-ups and when you arrive at your location can help catch a bad bearing before it becomes a major problem.
How To Repack Trailer Bearings
Grease is messy and finds its way everywhere as well as collects dirt easily. That being said, planning ahead and having everything you need will make the job easier. Before you jump into this maintenance task, let’s look at all the things you’ll need to repack trailer bearings.
- Wheel bearing grease
- New grease seals
- Brake cleaner
- Adjustable wrench or channel lock players
- Seal remover (flat screwdriver or punch will work)
- Wheel wrench
With everything ready to go and your trailer on a flat surface, you can jack it up and remove the first wheel. Always be careful when jacking your trailer, and use jack stands and wheel chocks for added support.
Accessing the Wheel Bearings
The dust cap will be the first thing to remove once the wheel is off. It’s important that the dust cap is in good condition and is fully enclosing the outer bearing. Dirt and bearings don’t mix, so if the dust cap is not in good shape, replace it.
Behind the dust cap, you will see a large nut that will likely be covered in grease. This is a castle nut, and it is designed to be only slightly tightened and held in place with a cotter pin or a tab washer. Straighten out the cotter pin or the tabs on the washer if you have one, and remove them.
Note: Cotter pins are for one-time use and should be replaced anytime they are removed.
The castle nut won’t be tight but may still require the use of a wrench. Behind the nut will be a washer, and that’s it for what holds the brake drum and bearings in place.
Removing the Wheel Bearings
The outer bearing will be free at this point but likely stuck to the drum assembly. Pulling the drum off will push the bearing out. Try to catch it so it isn’t damaged or dirty.
Place the bearing in a rag to keep it clean until you can inspect it. The inner bearing is held in place with a grease seal so it won’t fall out like the outer bearing. The inner seal needs to be pried out which usually results in damaging it. If you have a seal remover, you may be able to do it without damage; however, it’s best to replace the inner seal.
A flat screwdriver or punch can be used to pop the inner seal out as well. With the seal removed, the inner bearing can be removed. Again, keep it clean in a rag so it can be reused if it’s in good shape.
Inspecting the Bearings and Races
Before you repack trailer bearings, you must make sure they are still in good condition and don’t need to be replaced. Wipe all the excess grease off of the bearings and inside the hub. A brake cleaner can be used to completely clean out the hub for inspection.
If there was lots of grease covering the bearings and mounting surfaces, this is a good sign. If the grease was free of grit and still thick in consistency, you are probably in good shape. Heat is the worst enemy of bearings, and you can easily check for overheating with everything cleaned up.
The tapered surface the bearing sits on is called the race. Check this surface for blue or purple discoloration, which indicates high temperatures. The bearings will also have discoloration if they were subject to overheating. If everything looks good and the bearings have no damage or missing rollers, you can repack them.
How To Repack Trailer Bearings
Using fresh wheel-bearing grease and a new pair of gloves, take a generous amount of grease in your palm. With your other hand, you can hold the bearing with the tapered side facing up and press the outer edge into the grease. Continue doing this going around the circumference of the bearing until old grease is pressed out and replaced by new grease.
Once the rollers are packed with grease, you can coat the remainder of the bearing with grease. Ensure the entire bearing is coated, as well as the races and the spindle that extends through the brake drum. Take care not to get any grease on the brake drum or on the brake shoes. Clean any grease from the braking system with brake cleaner before reassembly.
This is also the time to check your brakes for wear and damage. Missing springs, cracked brake shoes, and worn-down brake shoes should all be addressed.
Reinstalling Wheel Bearings
Installation is essentially the reverse of disassembly, with a couple of important steps to follow. Keeping everything clean is the key. Dirt in a bearing can quickly destroy it, leaving you stranded.
The inner bearing will be installed first by simply placing it tapered side down into the rear of the drum. Next, the inner seal will be installed to hold the bearing in place. A new seal should be used to ensure it stays in place and holds the grease in and the dirt out.
Set the seal in place, and using something flat that covers the entire seal, gently hammer it in place. Ensuring it is going down evenly is important, and when installed, the seal should be flat.
The drum can be installed onto the wheel studs, and the outer bearing can be placed into the outer race. A washer will be next, followed by the castle nut. The nut should be spun on just until it makes contact and you feel resistance. The cotter pin or tab washer will only install with the nut in a certain position so you will have to adjust it slightly.
It is better to loosen the nut a little to accommodate the cotter pin or tab washer. Over-tightening the nut will put excess pressure on the bearings, which need to be able to spin freely.
It’s time to reinstall the cotter pin or tab washer to secure everything in place. Check that the drum spins freely and has limited play when wiggled from side to side before reinstalling the wheels. Some dust caps need to be installed before the wheels go on and some can be installed after.
Double Checking Your Work
Your first trip after you repack trailer bearings is critical for checking that everything is working as it should. Check for leaking grease on the front and back sides, as well as doing a temperature check on the wheel.
Keep in mind that repacking bad bearings isn’t going to get you very far. The benefit of repacking trailer bearings is to keep fresh grease in the bearing. Due to the temperature and high speed, grease breaks down over time and is much less effective at protecting the bearings.
Grease is messy and sticky, but it is also cheap and vitally important to your rig. Doing the minimum bearing service is a must for the health of wheel bearings. Doing this simple job in your driveway is much more enjoyable than changing a bearing on the roadside.