Trailer bearings: which type you have, and when they actually need grease

This is the first question because it decides whether you have a job at all. The two systems look identical from outside the wheel, and both are sold by the same company, so the answer comes from the axle itself rather than from the trailer.

E-Z Lube, and why it changes the job

Dexter's own definition is the clearest one: "If your axle is equipped with the Dexter E-Z Lube feature, the bearings can be periodically lubricated without removing the hubs from the axle. This feature consists of axle spindles that have been specially drilled and assembled with grease fittings in their ends."

The procedure is short, and the maker's five steps are worth following rather than improvising. Remove the rubber plug from the end of the grease cap. Put a standard manual grease gun onto the fitting in the end of the spindle and make sure the nozzle is fully engaged. While rotating the hub, pump grease in slowly, and the displaced old grease will come back out of the cap around the nozzle. When you see new clean grease, stop, wipe off the excess, and replace the plug.

Two details that people get wrong. The grease is specified on the E-Z Lube product flyer rather than in the service manual: "Use only LITHIUM COMPLEX NLGI CONSISTENCY #2 GREASE. Other types of grease may not be compatible." The manual attaches a caution to the same point, and it explains why the type matters: "Do not mix Lithium, calcium, sodium or barium complex greases due to possible compatibility problems. When changing from one type of grease to another, it is necessary to ensure all the old grease has been removed." And the gun matters, because the warning is about the tool rather than the technique: "Dexter strongly recommends not using pneumatic powered grease guns as these can inject grease too fast and force grease past the seal, or in rare cases dislodge the seal." A powered gun on a sealed cavity is how a bearing job becomes a brake job. The flyer states the system's scope as well: E-Z Lube is offered on "TORFLEX® and Sprung axles up to 8,000 lbs."

And the convenience is not a substitute for looking. Dexter states it directly: "The convenient lubrication provisions of the E-Z Lube and the oil lubrication must not replace periodic inspection of the bearings." Greasing a bearing with a failed seal fills the hub with grease and tells you nothing about the bearing.

Nev-R-Lube, which has no lubrication task at all

If your axle has Nev-R-Lube bearings, the maker's sentence is unambiguous: "They are lubricated, assembled and sealed at the factory. No further lubrication is ever needed." Its product literature lists the consequences as features: "No more inner and outer bearing to repack" and "No grease seal required".

That matters because the 10,000-mile rule sends an owner straight at a sealed unit. A worn Nev-R-Lube is replaced, not repacked. Dexter's remedy for a Nev-R-Lube unit showing excessive wheel end play, restriction to rotation, noise or bumpy rotation is to replace the bearing unit, which is what the sealed cartridge is designed to be. The cartridge is also not meant to come out for a look, only to be changed, so a shop that proposes to repack one is proposing to disassemble something that has no serviceable interior.

Where to find the answer on your own axle

The grease fitting is the tell. An E-Z Lube axle has one in the end of the spindle, visible under the rubber plug in the middle of the grease cap. If there is no fitting, and the hub carries a cartridge rather than two cones, it is almost certainly Nev-R-Lube. When in doubt, the axle's own tag or the trailer's paperwork names the model, and that is what the makers' documentation is organised around. One caveat on reading the fitting: a through-spindle system from another maker looks the same from outside, because Lippert's own guide describes its Super Lube system as a through-spindle arrangement too. The interval follows the maker rather than the fitting, so if the paperwork says Lippert, use Lippert's numbers, which are three times Dexter's.

The number repeated online is 10,000 miles. Neither maker publishes it.

What Dexter actually publishes

Dexter's light-duty service manual is direct: "Bearings should be lubricated every 12 months or 12,000 miles." The interval is given in both units.

Its maintenance chart carries four columns, "Weekly", "3 Months or 3,000 Miles", "6 Months or 6,000 Miles" and "12 Months or 12,000 Miles", and the two rows that matter here sit in the last one. Wheel bearings and cups: "Inspect for corrosion or wear. Clean and repack." Seals: "Inspect for leakage. Replace if removed." So a thousand miles of towing does not put you at a repack, and neither does six months.

The heavy-duty manual agrees on the mileage and adds the other interval for axles that run oil rather than grease: grease is replaced at "every 12,000 miles or 12 months", while "Oil should be changed at least once a year, or 100,000 miles, or whenever the seals or brakes are replaced. Oil level should be inspected every 1,000 miles." Checking and replacing are different jobs on different clocks, which is the distinction that gets lost when someone says "bearings every year".

What Lippert publishes, and it is different

Lippert builds trailer axles too, and its owner's manual gives a different number for the same task: "Bearing grease should be replaced every 36,000 miles or 12 months, whichever comes first."

Three times Dexter's mileage figure, from the other major axle maker, and published seven years later. The interval belongs to the axle you have, which is why the first section of this page is about identifying it rather than about reading a number. If you know the maker, use that maker's figure. If you do not, the twelve-month clock is the one both of them agree on.

What "inspect" means when the bearings are sealed

On a Nev-R-Lube axle there is still a schedule, and it is inspection rather than lubrication: "Bearing units should be inspected every year or 12,000 miles whichever comes first." Lippert draws the same line in its own words, separating "Periodic Bearing Inspection" from "Bearing Lubrication Inspection".

So on a sealed axle the scheduled task is watching for the symptoms the maker names, noise and roughness and play, rather than performing a service.

The other two bearing arrangements

The page has described two systems so far, and there are two more worth naming because a reader with one of them has no schedule yet. Plain greased bearings with no fitting in the spindle use the same twelve month or twelve thousand mile clock, but the hub comes off for the repack rather than the grease being fed in through the spindle. Oil-lubricated hubs run a different schedule entirely, and the maker gives it in the same document as the fitting: "If your axles are equipped with oil lubricated hubs, periodically check and refill the hub as necessary with a high quality hypoid gear oil to the level indicated on the clear plastic oil cap."

The heavy-duty manual puts figures on that clock, quoted above, and they make the contrast sharpest: an oil hub is checked far more often than it is serviced, which is the opposite of the greased arrangement, and a reader who assumes the two schedules are interchangeable has the wrong one.

This is the one instruction on the page whose cost is measured in brake parts rather than in time, and it is specific to the E-Z Lube system:

"If hubs are removed from an axle with the E-Z Lube feature, it is imperative that the seals be replaced BEFORE bearing lubrication. Otherwise, the chance of grease getting on brake linings is greatly increased."

Read the order carefully. The seal goes in before the lubrication, not after it, and the maker gives the reason in the same sentence: grease reaching the brake linings. What sits behind a trailer hub is the brake assembly.

The general rule for any hub that comes off is in the same manual: "Whenever the hub is removed, inspect the seal to assure that it is not nicked or torn and is still capable of properly sealing the bearing cavity. If there is any question of condition, replace the seal." Lippert is more direct still for its own axles: "Lippert recommends replacing the grease seal whenever bearing packing is required." And going back on, the heavy-duty manual attaches a second warning to the same failure: "DO NOT CONTACT RUBBER SEALING LIP WITH THE SPINDLE THREADS." A seal lip dragged across the threads does not seal afterwards, which puts the hub straight back at the top of this section.

If the trailer goes into the water, the answer changes the maintenance rather than a component:

"The E-Z Lube feature is designed to allow immersion in water. Axles not equipped with E-Z Lube are not designed for immersion and bearings should be repacked after each immersion."

And for the sealed system, the maker is equally clear: "Nev-R-Lube is not designed for immersion in water, such as boat trailer use."

So a boat trailer built on E-Z Lube axles has a maintenance answer, and a boat trailer built on Nev-R-Lube axles has a design mismatch. That is worth knowing before buying rather than after, because the difference is not visible in a photograph of the hub.

Bearing adjustment is where a well-meant repair goes wrong, and the two systems take different numbers. Do not carry one across to the other.

Nev-R-Lube: the spindle nut is torqued to a real figure, "145-155 Ft. Lbs.", and the manual explains why: "this torque will set the internal bearing adjustment, no other adjustments are to be made." The adjustment is inside the sealed unit and the nut's torque is how it is set, which is why the finger-tight habit from a standard axle is wrong here.

Standard bearings: the sequence is the familiar one, with the numbers attached. Tighten the spindle nut to "approximately 50 Ft. Lbs." while rotating the hub, "then loosen the spindle nut to remove the torque", then "finger tighten the spindle nut until just snug."

And the figure that catches people after the job, not during it. Wheel nuts have their own schedule, and it is not a single check: "Wheel nuts/bolts should be torqued before first road use and after each wheel removal. Check and re-torque after the first 10 miles, 25 miles, and again at 50 miles. Check periodically thereafter." A wheel that has just been off is the wheel to watch.

Two things on this page are not owner judgement calls, and the makers say so.

Jacking. Dexter is absolute about where the jack goes: "Do not lift or support the trailer on any part of the axle or suspension system. Never go under any trailer unless it is properly supported on jack stands which have been rated for the load. Improperly supported vehicles can fall unexpectedly and cause serious injury or death." That covers the axle and the suspension, and the positive half of the rule is a step in the same manual: "Elevate and support the trailer unit per manufacturers' instructions." The same manual gives that positively: "Jack up the trailer and place jack stands under the trailer frame so that the weight will be off the tires." and, in the same instruction, "Never jack up or place jack stands on the axle tube or on the equalizers."

Confidence. Dexter's own guidance is "If you are familiar with truck and trailer maintenance, feel free to follow the instructions below. If you do not feel confident performing truck or trailer maintenance, please take your vehicle to a service center to avoid injury." Its troubleshooting section ends the same way: "If you are unsure or unable to resolve the problem, please contact your nearest repair facility for professional assistance."

Bearings and brakes share an assembly, and a bearing that is adjusted wrong shows up as a wheel that runs hot, wobbles, or leaves. That is not a fault to diagnose from symptoms. On a sealed axle, if wheel end play, restriction to rotation, noise or bumpy rotation describes what you are feeling, the maker's remedy is a replacement rather than a repack, and that is a job for somebody who works on trailer axles. A plain greased bearing showing the same symptoms is a different job, because those come out and can be inspected. The directory lists mobile technicians and repair centres by state.

Brakes live in the same assembly and on the same inspection clock, which is the trailer brake guide. Tires and their load limits are in the tire replacement guide, and the weights that decide how hard all of it works are in the weight calculator. For the makers' own axle and brake documents, the manuals section has a towing and running gear page.