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How to Replace Your Boat Trailer Bearings? – 8 Steps to Do

Fact checked by William Hart

how to replace your boat trailer bearings

Does one of your boat trailer’s wheels make a weird noise? Does one wheel feel loose as you shake it? It’s time to examine and decide whether to repack or replace the bearings. Procrastinating is not an option here since your trailer can break down in the middle of the highway at any time.

How to replace your boat trailer bearings? Can I do it by myself? This article will walk you through the steps to inspect and change boat trailer bearings like a pro.

Table of Contents

Step-by-step to Replace Your Boat Trailer Bearings

What to prepare

You only need bearing grease and a jack and stand to repack boat trailer bearings. But you should prepare a boat trailer bearing kit if you intend to change the wheel bearings.

Besides, grab your toolbox, which should include the following:

  • A screwdriver
  • Channel locks
  • A hammer
  • A round punch
  • Needle-nose pliers
  • A bearing packer
  • A race tool

Step 1. Jack up the trailer


To begin, move your boat trailer to a flat and clean terrain. If you have a tow vehicle, fasten the couplers to secure the trailer and make sure the vehicle is with brakes.

If there isn’t a tow vehicle, find a method to fix the tongue of the trailer onto the ground.

Also, chock the tires with blocks. You don’t want the trailer to move while you are working.

When everything is set, place the jack underneath the trailer to raise it. Then, use a jack stand to secure the distance. You can replace the jack stand with a wood block, but it must be sturdy enough to withstand the weight of the trailer should anything go sideways.

Step 2. Examine the trailer’s wheel

Before dismantling the bearing system, check if it is necessary to do so. When you grip the tire with both hands and shake it from side to side, there should be a slight play but not too much. If the tire feels too loose, the bearings might have problems, and you should proceed to step three.

You can also inspect the wheel by spinning it and listening to the sound. Any weird or loud noise indicates potential bearing issues. However, the sound can be a problem with disc brakes, so don’t forget to check them as well.

Step 3. Remove the bearings’ fastening materials


A standard bearing construction begins with a dust cap on the exterior. Inside the cap, one cotter pin, one axle nut, and one spindle washer secure the outer bearing, which is housed in an outer race.

Next comes the hub—the wall that separates the bearings behind and in front of the wheel. Moving inward, you’ll find an inner race housing the inner bearing. Finally, you reach a double lip grease seal, which keeps the grease in the system from escaping and water from penetrating.

Before you can change bearings on trailer, remove all the fastening materials.

  • Use a screwdriver to unfasten the dust cap
  • Use needle-nose pliers or wire cutters to pull the cotter pin out of its position
  • Use a pair of channel locks to twist counterclockwise and remove the axel nut and spindle washer

As you continue to dismantle and inspect the bearing system, you will find out whether a boat trailer bearing replacement is necessary. If it is not, you shall reinstall these components. So, clean them with a paper towel and store them in order.

Step 4. Detach the outer bearing


The outer bearing will fall out as you shake the tire. Once you have it, first inspect the grease then wipe off the grease to check the bearing. You will need to change wheel bearings on a boat trailer if:

  • The grease has metal splinters in it
  • There are visible rust marks, black pits, brown spots, or dents on the bearing

Step 5. Detach the inner bearing

Now, pull the wheel off the trailer and place it flat on the ground. Then, pry the grease seal off with channel locks to get to the inner bearing. Light or milky grease inside the seal indicates that it has failed and water has penetrated, which means the seal needs replacing.

Once you have the inner bearing, inspect it as how you did with the outer bearing in the previous step. In case both bearings are in good condition, move to inspect the races that house them.

If the system shows no signs of defects, boat trailer hub replacement is not necessary. Follow this procedure to repack your boat trailer bearings and seals:

  • Clean the buildup grease and trash on the axle’s spindle of the trailer frame
  • Pack the inner bearing, and outer bearing, and races with fresh grease
  • Reinstall the components
  • Use a new seal and cotter pin to secure them

However, if the bearings and races are scarred and discolored, move to the next step.

Step 6. Remove the inner and outer races

Before grabbing your boat trailer wheel bearing kit and installing the new bearings, you need to remove the old races.

  • Lean the round punch tool onto the edge of one race
  • Gently tap the hammer as you move the tool around the edge
  • Keep tapping until the race falls out
  • Repeat for the other race

Step 7. Install new inner bearing


The process of trailer wheel bearing installation is converse with the disassembly. So, you begin by installing a new inner race:

  • Place the new outer race on top of the hub
  • Gently tap around the edge to slide it into the hub
  • Put a race tool on it and use the hammer to drive it into place

Now, pack the components with fresh grease before installing them:

  • Put a generous amount of grease in the hub. Don’t worry about applying too much, the excess will be pushed out when you secure the tire in place.
  • Slide the inner bearing into a bearing packer, press the tool, and move it side to side to pack the bearing with grease

Note: Use one type of grease for the entire procedure. Mixing types and brands can cause the grease to react with one another and alternate the consistency of the product, causing oil to drip out of your bearing system.

After that, glide the inner bearing into the inner race and secure it with a new double-lip grease seal. To install the grease seal, just place it on the race and tap to drive it into the slot. Remember to clean off any excess grease.

Step 8. Install the new outer bearing

Lift the wheel and secure it against the spindle of the axle. Then, do the same as the inner components to pack the outer bearing with grease, install the outer race, and insert the outer bearing into the race.

When the outer bearing is in place, you will lock it by:

  • Inserting the axle washer
  • Tightening the axle nut with channel locks
  • Sealing the nut with a cotter pin
  • Placing the dust cap on top to seal everything

Pay attention not to over-tighten the axle nut. You don’t want to put a lot of pressure on the bearings.

Other Tips to Replace Your Boat Trailer Bearings

  • Make sure to inspect and unplug the wheel hub to pick a bearing component compatible with each wheel axle’s spindle.
  • Pay attention to the loose bearings and their sounds when moving to determine a suitable time for a replacement or if the replacement is a success.
  • Always inspect the bearing to determine if they need replacement during boat maintenance every year.


How often should bearings be replaced on a boat trailer?

The lifespan of trailer bearings depends on many factors, such as road conditions, frequency of use, storage, and maintenance.

We recommend inspecting your wheel bearing systems every 3,000 to 3,500 miles or twelve months, then deciding whether they need repacking or replacing.

Most of the time, you won’t need to replace the bearings. As long as you perform proper routine maintenance, high-quality bearings can last up to 100,000 miles.

How much does it cost to replace bearings on a boat trailer?

The price of a bearing kit starts at $30. So, the cost of replacing bearings at home should be between $100 to $400 provided that you already own the necessary tools.

In addition, it takes around one hour to change the bearings of one wheel. If you plan to replace the bearings on all the trailer’s wheels, expect to spare at least one morning.

How often do boat trailer bearings need to be greased?

You should examine and repack trailer bearings every 3,000 to 3,500 miles or 12 months. Besides keeping the bearings functioning at their best, the annual maintenance chore will allow you to spot any defects in the bearing system and replace it in time.


That sums up our step-by-step guide on how to replace your boat trailer bearings. When you understand the construction of a bearing system, bearing replacement turns out to be rather easy and simple.

Now, you no longer have to bring the trailer to the shop, wait hours after hours, pay pricey bills, and drive a long distance towing your trailer back home.

If you’re still not confident in your skills, ask an experienced friend to assist you at the beginning. You will get used to such maintenance tasks in no time.

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