Greasing trailer bearings: how often, which grease and how to do it

Updated October 28, 2026 · Reviewed by Israel Margulies, founder and CEO of High Point GPS

Repack grease-lubricated trailer wheel bearings every 12 months or 12,000 miles, whichever comes first, which is the interval axle maker Dexter publishes for its standard and E-Z Lube axles. A repack means pulling the hub, cleaning out all the old grease, inspecting the cones and cups, packing fresh grease into the bearings, fitting a new seal and setting end play. Pumping grease into a fitting is a top-up between repacks and does not replace that inspection.

How often to grease trailer axle bearings

The axle maker sets the interval, and the number on the axle tag tells you whose manual to read. Dexter’s interval for grease-packed hubs is 12 months or 12,000 miles. Its oil-bath hubs on heavy axles follow a different rule: check the oil level every 1,000 miles and change the oil at least once a year, at 100,000 miles, or whenever the seals or brakes are replaced. Sealed cartridge bearings such as Dexter’s Nev-R-Lube never take grease, but Dexter still says to check them for play and rough rotation every year or 12,000 miles.

On a low-mileage trailer the 12-month limit comes due first. An equipment trailer that moves a mini excavator twice a month might cover 3,000 miles a year, so a mileage-only schedule would leave its grease in the hub for four years. Grease ages and picks up moisture while the trailer sits. Timken suggests doing the bearings before a trailer goes into long storage for that reason.

Grease-packed hubs (Dexter): repack every 12 months or 12,000 miles
Oil-bath hubs (Dexter heavy axles): check level every 1,000 miles, change yearly or at 100,000 miles
Sealed cartridge bearings: no grease, inspect yearly or every 12,000 miles
Boat trailers without E-Z Lube: Dexter says to repack after each immersion

Which grease to use on trailer wheel bearings

Dexter specifies an NLGI No. 2 grease with a lithium complex thickener, a dropping point of at least 419°F (215°C), and EP, corrosion and oxidation inhibitors. Its manual lists approved products from Chevron, Mobil, Shell, Valvoline and others, so you can match what you already stock against the list.

The bigger risk is mixing. Dexter warns that lithium complex grease mixed with a calcium, barium, clay or polyurea thickened grease can harden, separate or turn acidic. If you inherit a trailer and don’t know what is in the hubs, clean every trace of old grease out of the hub, bearings and cap before you pack with your own. Keep one wheel bearing grease in the shop and label the gun so nobody fills it with chassis grease.

How to repack trailer wheel bearings, step by step

Support the trailer on rated jack stands under the frame, never on the axle or suspension, and pull the wheel. The steps below follow the Dexter and Timken instructions for tapered roller bearings with a cotter pin or nut retainer.

Pry off the grease cap, remove the cotter pin or retainer, unscrew the spindle nut and slide the hub off without dropping the outer cone
Pull the seal and the inner cone, then wash every part in solvent such as mineral spirits or kerosene
Dry the cones with a lint-free cloth and never spin them with compressed air
Inspect each roller and cup; pitting, spalling, corrosion or heat discoloration means you replace the cone and cup as a set
Check the spindle seal journal for nicks and dress burrs with fine emery cloth
Pack each cone by pressing its wide end into a palm of grease, roller by roller, until grease pushes out the narrow end, or use a packer
Coat the cups with a light film, fit the inner cone and drive in a new seal evenly with a seal driver or a flat block of wood
Slide the hub on, fit the outer cone, washer and nut, then set the bearing adjustment as below

Setting bearing end play after a repack

Tapered roller bearings need a small amount of end play. Too tight and the bearing runs hot; Timken warns the wheel can lock or separate. Too loose and the rollers hammer the cups. The two manufacturers describe the setting differently, so use the one that matches your axle’s manual.

Dexter’s method for its 600 to 8,000 lb axles: turn the hub while tightening the spindle nut to about 50 ft-lb to seat everything, loosen the nut to zero torque without turning the hub, snug it finger tight, then back it off to the first castellation that lines up with the cotter pin hole. The nut should move, held only by the pin. Timken’s method: tighten to 25 ft-lb while turning the hub, back off 1/6 to 1/4 turn, then confirm 0.001 to 0.005 inch of end play with a dial indicator against the spindle end. Use a new cotter pin every time.

Greasing a trailer axle with E-Z Lube fittings

Axles with a grease fitting in the spindle end, such as Dexter E-Z Lube, let you push fresh grease through both bearings with the wheel on. Pull the rubber plug from the cap, seat a manual grease gun on the fitting and pump slowly while someone turns the wheel. Stop when clean grease appears around the nozzle, then wipe it off and refit the plug.

Two warnings from Dexter apply here. Don’t use an air-powered grease gun, because it can force grease past the inner seal and onto the brake shoes. And the fitting does not replace inspection: you still have to pull the hub on schedule to look at the rollers and seal. Timken goes further and advises against spring-loaded bearing protectors, which can overfill the hub until heat and pressure push grease out through the seal and let dirt in.

Signs a trailer wheel bearing needs repair

A trailer has no dash light for its hubs, so the driver’s walkaround and a hand on the hub at fuel stops are your warning system. Timken lists these indicators of wheel end damage. Any one of them should take the trailer out of service until someone pulls the hub.

Grease or oil streaks on the wheel, tire sidewall or inside of the rim
A hub or cap that is much hotter than the others after a run, or smoking
Growling, grinding or a rumble that changes with speed
Wheel wobble, play when you rock the top of the tire, or abnormal tire wear
Inside the hub: dry caked grease, metal particles, or blue and brown heat stain on a cone

Tracking trailer axle maintenance in FleetZap

In FleetZap you add each trailer as an asset, with a photo of the axle tag and the axle manual attached as documents, then assign a calendar preventive maintenance schedule every 12 months to all trailers in the category at once. FleetZap opens the repack work order when it falls due. Trailers fitted with an optional GPS tracker can run on a mileage schedule as well, since meter-based schedules skip units without a meter.

Attach a procedure to the schedule so every repack arrives with the same steps: a reading step for end play with min and max limits, a photo step for the cones, and a sign-off. A reading outside the limits counts as a failed step. List the bearing kit, seals and cotter pins as spare parts on each trailer so the technician sees them in the part picker. Drivers scan the trailer’s QR label for the pre-trip check; a failed “no grease leaking from hubs” item opens one linked repair work order, and the problem code on that repair builds the failure history you see in Reports.

Key takeaways

If a trailer's yearly mileage is under 12,000, put it on the calendar schedule only; a mileage trigger will never fire first.
Buy grease by the axle maker's spec sheet and keep the product name in the procedure, so a new tech can't grab whatever tube is nearest.
When a repack turns up one bad cone, open the other hubs on that axle in the same visit; they carry the same miles and the same grease.
Stock seals and cotter pins per trailer; you replace both on every hub you open.

Sources

Frequently asked questions

How often should you grease trailer bearings?

Follow your axle maker’s manual. Dexter, a common US trailer axle maker, sets a yearly or mileage interval for grease-packed hubs and says to service at whichever comes first, so a trailer that rarely moves still gets a repack every year. Boat trailers without a sealed, immersible design should be repacked after every dunking, according to Dexter.

Can you grease trailer bearings without removing the hub?

Only if the axle has a grease fitting in the spindle end, such as Dexter E-Z Lube. Pump slowly with a manual gun while turning the wheel until fresh grease shows at the cap. That refreshes the grease but lets you see nothing inside, so you still pull the hub on the scheduled interval to inspect the bearings and seal.

What kind of grease goes in trailer wheel bearings?

Dexter specifies NLGI No. 2 lithium complex grease with a dropping point of at least 419°F and EP, rust and oxidation additives. Don’t mix it with calcium, barium, clay or polyurea based greases, because incompatible thickeners can harden or separate. If you switch products, clean all the old grease out of the hub and bearings first.

How tight should a trailer wheel bearing nut be?

Snug, then backed off slightly. Dexter seats the bearing at about 50 ft-lb, loosens the nut, snugs it by hand and backs it to the first cotter pin hole. Timken tightens to 25 ft-lb, backs off 1/6 to 1/4 turn and checks for 0.001 to 0.005 inch of end play. Use your axle maker’s method.

When does a trailer wheel bearing need repair instead of a repack?

Replace the cone and its cup as a set when you find pitting, flaking, corrosion, heat discoloration or dents on a roller or race, or metal particles in the grease. Replace the seal on every hub you remove. A hub that ran hot, leaked or growled on the road needs a teardown and inspection before the trailer goes back out.

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