Repacking Trailer Bearings with Electric Brakes
Dealing with a trailer can be tedious at times, especially when it comes to maintenance and repairs. One critical component that requires regular servicing are the wheel bearings. If neglected, worn bearings can fail suddenly and cause extensive damage.
Trailers with electric brakes add an extra layer of complexity during wheel bearing maintenance. The brake components must be handled carefully to avoid damage and ensure proper operation. Repacking wheel bearings on trailers with electric brakes is completely doable for a DIYer but does require patience and the right process.
In this guide, I will walk you through the entire process step-by-step, from start to finish, for safely repacking trailer wheel bearings that have electric brakes. Follow along to learn the required tools and supplies, tips for removal and disassembly, how to thoroughly pack the bearings with grease, proper reassembly and installation techniques, and testing the electric brakes before heading out on the road.
Gather Tools and Supplies
Having the proper tools and supplies on hand will make the trailer wheel bearing job much smoother. The basic items needed include:
Jack, Jack Stands, and Lug Wrench
– A hydraulic bottle jack or floor jack is needed to lift the trailer enough to remove the wheel. Always use jack stands for safety when working underneath.
– An adequate lug wrench that fits the lug nuts is required to remove the wheel.
Basic Hand Tools
– Standard screwdrivers, pliers, and a hammer come in very handy during wheel bearing jobs.
– Penetrating fluid may be useful for freeing up stubborn parts during disassembly.
Cleaning Supplies
– Wheel bearing grease is essential to thoroughly repack the bearings and races. Use a high quality water-resistant grease.
– Brake cleaner spray helps remove old grease and debris when cleaning the wheel hub components.
– Rags and kerosene are useful for wiping down parts. Avoid solvents which can damage rubber seals.
Specialty Tools
– A bearing packer tool, while not essential, makes quick work of forcing grease into the bearings. Manual packing with a screwdriver is tedious.
– Refer to the trailer shop manual for proper torque values, cotter pin size, bearing sizes, etc.
Prepare the Trailer and Remove the Wheel
With all the needed tools gathered, now the process of repacking the wheel bearings can begin:
Block the Opposite Wheel and Loosen Lugs
– Chock the wheel diagonal from the one being serviced to keep the trailer from rolling.
– Before jacking up the trailer, break all lug nuts loose while the wheel is still on the ground. Don’t remove it completely yet.
Jack Up the Trailer
– Position the jack under the trailer’s frame near the wheel to be serviced. Raise the jack enough so the tire is lifted off the ground 2-3 inches.
– Place jack stands under the frame as a safety measure before working underneath the trailer.
Remove the Tire/Wheel Assembly
– With the wheel no longer contacting the ground, finish unscrewing the lug nuts by hand or with the lug wrench, then pull the wheel off the hub.
– Set the tire/wheel aside to gain full access to the hub.
Remove Dust Cap and Cotter Pin
Before the hub can be removed, a couple small components need to come off first:
Pry Off Dust Cap
– Take a flat head screwdriver and gently pry out the plastic dust cap covering the wheel hub.
– This cap keeps contaminants out of the wheel bearings. Some persuasion may be needed if it is stuck on from old grease and dirt.
Straighten and Remove Cotter Pin
– Locate the cotter pin inserted horizontally through a hole in the spindle nut.
– Use pliers to straighten out the cotter pin legs.
– Then carefully pull the cotter pin fully out of the hole and set it aside. It gets replaced with a new one during reassembly.
Remove the Hub Assembly
With the cotter pin and dust cap out of the way, the hub can now be detached to access the wheel bearings.
Remove Spindle Nut and Washer
– Use the correct size wrench to hold the spindle shaft stationary while unscrewing the spindle nut.
– Slide off the outer spindle washer that sits behind the nut.
Pull the Hub off the Spindle
– With the nut and washer removed, carefully pull the hub and bearing assembly straight out off the end of the spindle shaft.
– Let the outer bearing cone drop out as the hub comes off. Catch the bearing before it falls to the ground.
– The inner bearing cone will still be seated inside the hub. Leave it there for now.
Clean and Inspect Bearings and Hub
Before repacking, all the wheel end components must be cleaned and inspected for signs of wear or damage:
Thoroughly Clean All Parts
– Soak and brush the bearings, hub and spindle in kerosene to remove all old grease, dirt and residue.
– Use brake parts cleaner spray to flush away any remaining gunk.
Inspect Bearings, Seals and Races
– Look for any pitting, discoloration, cracking or abnormal wear on the bearing balls, races, and cages.
– Make sure the grease seals are supple and undamaged.
– Spin the bearings smoothly by hand feeling for any roughness or binding.
Check Hub and Spindle Mounting Surfaces
– Inspect the hub and spindle shaft surfaces for any gouges, rust or burrs that could prevent proper mounting.
Replace Any Damaged or Worn Parts
– If wear or damage is found on any components, they must be replaced to avoid future failure.
Pack Bearings with Grease
The empty bearings can now be repacked full of fresh grease:
Use a Bearing Packer Tool
– A bearing packer presses grease thoroughly between the individual bearing balls and rollers. This is the preferred method.
– Alternatively, pack by hand using a screwdriver if a bearing packer is unavailable.
Work Grease Into the Bearing
– Add a glob of grease into the bearing packer or directly into the bearing.
– Turn the bearing around, pressing the grease into all the nooks and crannies around each ball.
– Repeat until the bearing is completely saturated in fresh grease. Don’t skimp.
Apply Grease to the Bearing Cups
– Put a thin layer of grease into the inner and outer bearing cups that sit in the wheel hub.
Reinstall Hub Assembly onto Spindle
With clean, greased up bearings, the hub components can be reassembled in reverse order:
Install Inner Bearing and Seal
– Pack the inner bearing cone with grease if not already done.
– Carefully press the greased inner bearing into the hub bore by hand. Avoid using a hammer.
– Install a new inner seal into the hub if the original one was removed or damaged.
Slide Hub with Inner Bearing onto Spindle
– Grease the spindle shaft surface lightly.
– Carefully slide the hub back onto the spindle being cautious not to dislodge the inner bearing seal.
Install Outer Bearing, Washer and Nut
– Place the freshly packed outer bearing cone in the outer hub race.
– Put the outer spindle washer on followed by the spindle nut.
Tighten Nut While Rotating Hub
– To seat the bearings properly, tighten the spindle nut down snug while slowly spinning the hub assembly.
– Do not over tighten initially. The final torque will be done after cotter pin insertion.
Install New Cotter Pin
– Back the spindle nut off just enough to line up the nut slots with the cotter pin hole in the spindle shaft.
– Insert a new cotter pin through the slots and hole, then bend the legs to secure.
– The hub should turn, but not wobble, when properly preloaded.
Final Nut Torque with Torque Wrench
– Use an inch-pound torque wrench to tighten the spindle nut to the specification in the trailer manual. Do not over or under torque.
Reinstall Wheel and Dust Cap
The bearings are now correctly packed and secured. All that remains is to remount the wheel and hubcap:
Mount Tire/Wheel and Tighten Lugs
– Apply a thin coat of anti-seize lubricant to the wheel lug threads to prevent corrosion sticking.
– Lift wheel into place aligning studs with holes. Hand thread lug nuts evenly.
– Snug lug nuts in a star pattern with the lug wrench to the proper torque spec.
Gently Tap Dust Cap Back In
– Once the wheel is fully secured, place the dust cap back over the hub end.
– Carefully tap around the edges with a mallet to press the cap back into place.
Test Electric Brakes Before Driving
The final critical step is verifying proper brake function before towing the trailer:
– Connect trailer wiring to tow vehicles and cycle the breakaway switch.
– Simulate a manual brake application by hand using a trailer brake controller.
– Confirm firm brake pressure and that all brakes activate evenly.
– Fix any issues immediately if brakes feel spongy, weak or do not engage fully.
– Road test at low speeds listening and feeling for any abnormalities before towing at highway speeds.
Taking the time to properly repack the wheel bearings and confirm the electric brakes work correctly ensures many more miles of reliable service from your trailer. Set a reminder to re-grease the bearings annually as preventative maintenance for best results. Just follow the steps outlined above and you can keep those trailer wheels happily rolling down the road.
People Also Ask (PAA)
Q1: How do I know if a bearing is worn out?
A: Check for visible damage like pitting, embedded metal flakes in the grease, looseness or wobble in the bearing, and excessive play when rotated. Grinding, popping or unusual noise when spinning means replacement is needed.
Q2: How often should trailer wheel bearings be repacked?
A: For average use, plan to repack trailer wheel bearings about once yearly. Towing frequently, in wet conditions, or with heavy loads requires more frequent repacking every 6 months.
Q3: Can I adjust bearing preload instead of replacing bearings?
A: No, worn bearings must always be replaced. Adjusting just the wheel nut preload cannot compensate for bearing wear or play from damaged surfaces.
Q4: What grease should be used when repacking trailer wheel bearings?
A: Use a high quality, water-resistant wheel bearing grease meeting NLGI GC-LB certification with lithium-complex or molybdenum disulfide additives.
Q5: Do I need a press to install wheel bearing seals?
A: No, gently tapping the seals into place by hand with a hammer and wood block is adequate for DIY bearing repacking as long as they are flush and straight.
Q6: Can I tow my trailer without properly packed wheel bearings?
A: It is not recommended. Driving without adequate grease can cause the bearings to overheat, seize and fail. This could result in a wheel coming off while towing.
Q7: What causes trailer wheel bearings to wear out prematurely?
A: Common causes are improper preload, contaminated or insufficient grease, excessive heat from brakes, moisture, too much weight on the wheel, and lack of regular repacking.
Q8: Should I replace or clean and repack wheel bearings?
A: If the bearings are in generally good condition with minimal wear, periodic cleaning and repacking is appropriate. Heavily worn or damaged bearings should be fully replaced.
Final Words
Properly maintaining your trailer wheel bearings is crucial for safe trouble-free towing. Following the steps outlined in this guide will help you expertly repack the bearings on trailers equipped with electric brakes. Taking the time to regularly service the wheel bearings and test the brake function will give you confidence in your trailer and keep you rolling smoothly down the highway. Consistent preventative maintenance is key to avoiding costly roadside breakdowns.
