You park the trailer after the last haul of the season, thinking you’ll get to it later. Then spring comes and you’ve got low tires, a weak battery, a corroded coupler, seized hardware, or evidence that something small and furry has been living in the tongue box all winter. It happens more often than most trailer owners expect.
Proper winter storage isn’t about being precious with your equipment. It’s about spending one solid afternoon now instead of paying for tires, wiring, bearings, brakes, batteries, or hydraulic repairs in March. The exact maintenance procedure depends on the trailer’s axle, hub, battery, brake, and hydraulic configuration, but the following seven steps cover what most work trailers need before an Indiana winter.
1. Tires: Pressure and Blocking
Cold weather lowers tire pressure, but not as dramatically as some people assume. Inflation pressure generally changes by about 1 to 2 PSI for every 10-degree Fahrenheit change in ambient temperature. A tire set correctly during a warm October afternoon can therefore be several PSI low after a prolonged January cold snap. Tires also lose some air naturally over time, so the pressure should be checked during storage rather than set once and forgotten.
Check every tire when it is cold, meaning the trailer has been parked for at least three hours. Inflate it to the cold pressure shown on the trailer’s certification label, tire placard, or owner’s manual. Do not use the tow vehicle’s door placard, and do not automatically assume that the maximum pressure molded into the tire sidewall is the correct target. Many trailers equipped with ST tires do specify a cold pressure equal to the tire’s maximum sidewall pressure, but the trailer manufacturer’s label remains the first reference. Never exceed the pressure limit of either the tire or the wheel.
Include the spare in the inspection. Confirm that every tire matches the required size, load range, and load capacity, and inspect the tread, sidewalls, valve stems, and bead areas for cuts, bulges, punctures, exposed cords, severe cracking, or recurring pressure loss. A tire that repeatedly loses air needs to be inspected and repaired or replaced instead of being continually topped off.
For extended storage, unload the trailer so the tires and suspension are not carrying unnecessary weight. If the trailer and axle manufacturer permit it, the best way to reduce prolonged tire deflection is to lift the unloaded trailer and support the frame on properly rated jack stands at approved support points. Lift and support the trailer by the frame, never by the axle tube, leaf springs, equalizers, or other suspension components. Chock the wheels before lifting, work on a firm and level surface, and never go under a trailer that is supported only by a jack.
If you cannot safely remove the weight from the tires, park on a firm, reasonably level, clean, and well-drained surface. Smooth plastic tire pads, rubber pads, or sound treated planks can separate the tires from mud, standing water, and rough gravel. Avoid sharp-edged lumber, damaged pallets, soft ground, or unstable stacks of material. Unload the trailer as much as possible and move it enough to change the tire contact area at least once every three months. Storage-related flat spotting is often temporary, but vibration that remains after the trailer has returned to service should be inspected.
Protect the tires from prolonged sunlight and weather with opaque tire covers. Clean them with mild soap, water, and a soft brush before storage, then let them dry. Skip petroleum-based dressings, harsh solvents, and unapproved tire treatments, which can accelerate deterioration rather than prevent it. Keep the tires away from spilled fuel, oil, battery chargers, welding equipment, and other sources of chemicals, heat, or ozone.
2. Battery: Remove or Maintain
Not every cargo trailer or trailer with electric brakes has a large onboard battery. Normal electric trailer braking power comes from the tow vehicle through the brake controller and seven-way connection. A separate battery may be installed for the emergency breakaway system, while dump trailers, hydraulic tilt trailers, winch-equipped trailers, powered jacks, and accessory-heavy enclosed trailers may carry a much larger deep-cycle battery.
Start by identifying every battery on the trailer. That may include a hydraulic-system battery, a winch or accessory battery, and a smaller dedicated breakaway battery. Record the battery type and rating before connecting a charger. Flooded lead-acid, AGM, gel, and lithium batteries do not all use the same charging profile, and a charger that is appropriate for one chemistry may damage another.
Charge lead-acid batteries fully before storage, clean corrosion from the terminals, check the case for swelling or cracks, and make sure the hold-down hardware is secure. If the trailer or battery manufacturer recommends removal, store the battery upright in a cool, dry, well-ventilated location protected from weather, flames, sparks, children, and pets. A heated basement is not necessary. Cooler temperatures slow lead-acid self-discharge, provided the battery is kept charged.
Use an automatic battery maintainer that is compatible with the battery’s chemistry and capacity. Do not select a charging rate from a generic rule when the battery label or manufacturer provides a specific requirement. If continuous maintenance charging is not available, check the state of charge periodically and recharge according to the battery manufacturer’s instructions. Lippert’s extended-storage guidance for a breakaway battery calls for removing it from the weather and charging it at least every 90 days.
If a lead-acid battery remains on the trailer, disconnect the negative cable or use the installed battery disconnect, unless doing so would interrupt an approved maintainer or charging system. Protect disconnected cable ends so they cannot contact the terminal or frame. A fully charged lead-acid battery resists freezing at temperatures far below a normal Indiana winter, while a deeply discharged battery may freeze at approximately 15 degrees Fahrenheit. Cold also reduces available battery capacity, which is another reason to begin storage with a full charge.
Lithium batteries require their own storage procedure. Some lithium batteries must not be charged below freezing unless they have built-in low-temperature protection or heating. Follow the battery maker’s storage-state-of-charge and temperature instructions instead of treating the battery like a conventional lead-acid unit.
Inspect the breakaway switch, cable, battery box, wiring, and built-in charger while you are there. Do not leave the breakaway pin pulled as a parking brake; that can drain the battery and overheat the brake magnets. Before the trailer returns to service, reconnect and fully charge the battery, test the breakaway system according to its instructions, and verify normal brake operation with the tow vehicle. Indiana requires brakes on trailers over 3,000 pounds GVWR, but the battery and breakaway arrangement still depends on the trailer’s specific brake system.
3. Grease Every Fitting Now
Winter moisture is hard on exposed pivots, couplers, jacks, suspension hardware, and wheel ends. Lubricating the correct components before storage leaves a protective film in place and gives you an opportunity to find worn, contaminated, or damaged parts before the trailer sits for several months.
First identify which components actually have grease fittings. A tandem-axle trailer with spindle-lubrication fittings normally has one fitting at each wheel end, for a total of four. A triple-axle trailer normally has six. Suspension wet bolts, ramp pivots, coupler parts, and jacks may have additional fittings, but many bushings and pivots are permanently lubricated or use a different maintenance method. Do not force grease into a component that was not designed to accept it, and do not coat brake parts, electrical contacts, safety-chain links, or tie-down hardware indiscriminately.
Current Diamond C trailers use Lippert axles, with the wheel-end system varying by axle and GVWR package. Some use Lippert Super Lube grease hubs, while heavier configurations may use oil-bath hubs. Check the axle tag, hub cap, trailer build information, and applicable Lippert manual before servicing. A rubber plug in the center of a grease cap commonly indicates a Super Lube spindle, while a clear oil cap and visible fluid level indicate an oil-bath hub.
When servicing a Lippert Super Lube hub, lift the trailer by the frame and support it safely so the hub can rotate. Remove the rubber plug, attach the grease gun to the spindle fitting, and slowly add the specified grease while continuously rotating the hub. The displaced grease exits through the front of the hub around the outer bearing. Stop when clean, fresh grease appears, wipe away the excess, and reinstall the plug. Pumping rapidly, failing to rotate the hub, or continuing after abnormal resistance can damage the rear seal and force grease onto the brake linings.
Use the grease specified for the axle. Lippert commonly calls for a high-quality NLGI No. 2 lithium-complex wheel-bearing grease with extreme-pressure, corrosion, and oxidation protection, but the manual for the exact axle remains controlling. Do not mix incompatible grease thickener types. If you do not know what grease is already in the hub, a complete inspection, cleaning, and repack is safer than adding an unidentified product.
A grease fitting is not a substitute for periodic wheel-bearing and brake inspection. Wheel ends must still be inspected at the interval specified by the axle manufacturer, and leaking seals, loose bearings, contaminated brakes, noisy hubs, or unusual heat require service. If grease is visible on the inside of a wheel, backing plate, brake drum, rotor, or brake wiring, stop and have the wheel end inspected before towing.
Oil-bath hubs do not receive wheel-bearing grease through a spindle fitting. Inspect the oil level through the clear cap, look for cloudy or discolored oil, and check the cap, plug, seal, and inside of the wheel for leakage. Use only the specified gear oil and filling procedure. A low oil level or active leak should be corrected before storage rather than topped off and ignored.
Lubricate the coupler latch, gooseneck components, jack gears or inner tubes, ramp hinges, and other approved moving points with the product specified by the component manufacturer. Cycle each mechanism after lubrication so the product reaches the working surfaces. Check that the coupler closes and locks correctly, the jack operates smoothly, and the safety latch or retaining pin is present. Wipe away heavy excess that would hold dirt or contaminate nearby brake and electrical components.
4. Rodent Prevention
Rodents do not care whether the trailer is a basic utility model, a premium enclosed cargo trailer, or a heavy-duty equipment hauler. They care that it provides shelter and contains wiring insulation, paper, fabric, seed, or other material they can chew or use for a nest.
A mouse can enter through an opening approximately 1/4 inch wide and can cause substantial damage to lighting circuits, electric-brake wiring, breakaway wiring, hydraulic controls, battery cables, insulation, and stored equipment. Exclusion, sanitation, and properly placed traps are more dependable than scent-based repellents.
Before closing up for the season:
- Inspect wiring grommets, door corners, floor penetrations, vents, conduit openings, roof transitions, and gaps around the tongue or rear frame. Seal small openings with knitted copper mesh or another rodent-resistant metal material secured with an appropriate sealant. Steel wool can work as a temporary plug but may rust. Use sheet metal or 1/4-inch hardware cloth for larger openings, and do not block designed drains, vents, or wire movement.
- Remove food, bird seed, livestock feed, pet treats, grain bags, trash, paper towels, cardboard, gloves, fabric, and other nesting material. Store straps, clothing, and soft accessories in sealed containers rather than leaving them loose inside the trailer.
- Place snap traps along walls or edges where rodents travel, with the trigger positioned toward the wall. Use tamper-resistant trap enclosures when children or pets could reach the area, and check traps regularly. Avoid loose poison inside the trailer, where a rodent may die in an inaccessible cavity and where bait can endanger pets or wildlife.
- Inspect the storage area around the trailer. Cut tall grass and weeds, remove brush and debris, and keep feed, garbage, and wood piles away from the unit. A sealed trailer is easier to protect when the surrounding area is not providing food and nesting cover.
For open-deck trailers, inspect every enclosed or shielded location, including the tongue box, hydraulic and battery compartments, toolboxes, spare-tire carrier, ramp storage area, under-deck wiring runs, and gooseneck storage space. Leave lids and doors fully latched after confirming that the compartments are clean and dry.
If you find droppings or nesting material in the spring, ventilate the trailer before cleaning. Do not dry-sweep or vacuum contaminated material. Wear gloves, wet the material thoroughly with an appropriate disinfectant, allow the required contact time, and remove it in accordance with the disinfectant and public-health instructions.
5. Cover It (But Vent It)
Covered, well-ventilated storage is best, but a properly fitted trailer cover can also reduce exposure to direct sun, snow, leaves, bird droppings, and repeated wetting. The trailer must be clean and completely dry before it is covered. Trapping road salt, mud, fertilizer, stone dust, or moisture underneath a cover can accelerate corrosion and damage the deck or finish.
Wash the frame, crossmembers, suspension area, fenders, deck, coupler, wheels, and underside with particular attention to road salt and deicing residue. Keep high-pressure spray away from wheel-bearing seals, brake electrical connections, hydraulic breathers, door seals, and other areas the manufacturer warns against pressure washing. Let the trailer dry thoroughly before closing compartments or installing a cover.
Inspect the coating while the trailer is clean. Diamond C’s DM Difference Maker multi-stage coating system provides durable corrosion, chip, abrasion, and color protection, but no coating can protect bare steel after a deep chip or impact. Clean and repair damaged areas with a manufacturer-approved touch-up procedure before winter moisture reaches the exposed metal. Pay special attention to the coupler area, fender edges, ramp contact points, stake pockets, tie-down locations, and the underside of the frame.
Use an opaque, weather-resistant cover with ventilation rather than wrapping the trailer tightly in an unvented plastic tarp. Support the cover so rain and melting snow drain instead of forming heavy pockets. Secure it well enough that wind cannot whip the material against painted surfaces, lights, decals, roof edges, or sharp corners. Padding at contact points can reduce abrasion, but the cover still needs airflow to prevent a sealed, damp environment.
Enclosed trailers do not always need a full-body cover, but they still need attention. Inspect roof seams, exterior fasteners, vents, door seals, hinges, weather stripping, and weep or drain openings. Clean the roof and make sure water cannot collect around damaged sealant or low areas. Leave only the ventilation openings intended by the trailer manufacturer; do not prop a cargo door open where wind, animals, or precipitation can enter.
For a wood deck, remove packed dirt and organic debris from between the boards and let the lumber dry. Apply a penetrating wood treatment only when it is compatible with the deck material, the wood is dry enough for application, and the product instructions permit use before cold weather. Do not allow deck treatment, oil, or solvent to reach the tires, brakes, wiring, painted coating, or reflective tape.
Check the trailer and cover after major wind, ice, or snow events. Tighten loose cover straps, remove water pockets, and clear excessive snow without damaging the roof, deck, lights, or coating. A cover protects the trailer only while it remains secure, ventilated, and capable of shedding water.
6. Fuel in Attached Equipment
If you haul engine-powered equipment such as a generator, mower, ATV, pressure washer, or compact tractor, the winter storage checklist extends to that machine. Whenever practical, unload the equipment before storing the trailer. That reduces weight on the trailer tires and suspension and allows the machine to be maintained in a safer, more appropriate location.
Do not run an engine inside an enclosed trailer, garage, or other confined space. Carbon monoxide can accumulate quickly, and gasoline vapors can ignite around heaters, switches, motors, chargers, and other spark sources. Fuel-powered equipment should be stored only in a location permitted by the equipment manual and applicable fire-safety requirements.
Gasoline can begin deteriorating in as little as 30 days, although the actual rate depends on the fuel blend, temperature, humidity, and condition of the fuel when purchased. Old gasoline can leave gum and varnish in carburetor passages, injectors, pumps, and fuel lines. Use the machine manufacturer’s storage procedure rather than applying one method to every engine.
The two common procedures are:
- Drain the fuel tank and carburetor as directed by the owner’s manual. Drain fuel into an approved container in a well-ventilated outdoor area after the engine has cooled. On a carbureted engine, simply running the engine until it stalls may not remove all fuel from the tank or carburetor bowl, so use the specified drain screw, valve, or hose procedure. Do not run an electronic-fuel-injection system dry unless the manufacturer specifically instructs you to do so.
- Fill with fresh fuel and add the exact amount of stabilizer approved for the engine and fuel blend. If the manufacturer recommends a full tank for storage, filling it reduces the air space in which moisture can condense. Run the engine outdoors for the instructed period, commonly several minutes, so treated fuel reaches the carburetor, injectors, pump, and lines. Then shut the engine down and close the fuel valve if the machine has one.
Fuel stabilizer preserves fresh fuel; it does not restore gasoline that is already stale or contaminated. Mark stored fuel containers with the purchase date, keep them tightly closed, and use only approved containers kept away from ignition sources. Inspect fuel hoses, shutoff valves, tank caps, and carburetors for seepage before leaving the equipment unattended.
Diesel storage requires a different approach. Use fuel meeting the engine manufacturer’s specifications, keep water and sediment out of the system, and service the water separator if equipped. Use winter-blended fuel or an approved anti-gel additive only when required for the expected temperature and allowed by the engine manufacturer. Microorganisms, sometimes loosely called diesel algae, grow where water is present in stored fuel. Do not add a biocide automatically; investigate water contamination and consult the engine manufacturer or fuel supplier before treating the system. Biodiesel blends may require special handling or replacement with conventional diesel before storage lasting more than 90 days.
7. Elevate the Frame
The storage surface matters even when the trailer frame does not directly touch the ground. Bare soil, deep vegetation, standing water, and poorly drained gravel keep the undercarriage in a damp environment. Repeated wetting can accelerate corrosion on frame edges, crossmembers, spring hangers, fasteners, brake backing plates, wiring clips, and exposed steel.
A paved surface is convenient, but a firm, compacted, well-drained gravel pad can also work. Remove weeds and debris, correct low spots where water collects, and place suitable pads under the tongue jack, stabilizing stands, and tires. The pads must be wide and strong enough to prevent sinking or shifting through freeze-thaw cycles.
If the trailer will be elevated, unload it and use jacks and stands rated for the trailer’s weight. Follow the trailer manufacturer’s approved lift and support locations, keep the unit level and securely chocked, and place the stands under structural frame points. Never support a trailer on hollow concrete masonry blocks, loose bricks, an unstable pile of lumber, the axle tube, or the suspension. A tongue jack or hydraulic jack is a lifting device, not the only support for a trailer under which anyone will work.
While the trailer is safely positioned, inspect the frame rails, crossmembers, coupler structure, welds, spring hangers, leaf springs, equalizers, shackles, bushings, U-bolts, brake wiring, hydraulic hoses, and axle mounting hardware. Look for cracked welds, bent components, broken spring leaves, elongated bolt holes, missing fasteners, loose wiring, leaking seals, rubbing hoses, and fresh rust around joints. Rust trails or polished metal around a fastener can indicate movement.
U-bolt and suspension torque is not universal. It changes with the axle capacity, U-bolt diameter, fastener grade, suspension design, and axle package. A 3,500-pound Lippert axle does not use the same U-bolt torque as a 7,000-, 8,000-, 10,000-, or heavier axle. Identify the axle and suspension by its tag or build information, then use the applicable Lippert or component-manufacturer specification and a calibrated torque wrench. Do not guess from the trailer’s GVWR, and do not use an impact wrench for final torque.
If a U-bolt is visibly damaged, heavily corroded, stretched, loose after repeated tightening, or removed during suspension service, ask the axle manufacturer or a qualified trailer technician whether replacement is required. Tightening a compromised fastener is not a repair. Finish by treating any approved exposed pivot points and repairing coating damage before the trailer is lowered or left on stands for storage.
One More Thing Before You Walk Away
Take five minutes and document the trailer’s condition with your phone camera. Walk around the entire unit and photograph the deck, body panels, roof, frame, coupler, jack, safety chains, breakaway switch, tires, spare, lights, battery compartments, hydraulic equipment, ramps, and license plate. Include clear photos of the VIN and certification label, axle tags, tire DOT date codes, battery labels, and any existing damage.
Write down the cold tire pressures, battery voltage or state of charge, bearing-service date, and any maintenance completed. Keep the notes with the trailer’s manual, build sheet, receipts, and component documents. That record makes spring setup easier and gives you a reliable baseline if you discover storm damage, theft, corrosion, or a warranty concern.
Use the inspection to make a repair list for the off-season. Worn safety chains, a damaged breakaway cable, loose deck boards, a cracked light lens, exposed wiring, a leaking hydraulic fitting, a weak battery, or a coupler with excess movement should be corrected before the next hauling job. Spring is busy hauling season. Ordering parts and scheduling service while the trailer is parked is much easier than discovering the problem on the morning you need it.
Before leaving the storage area, close and lock all compartments, cover the electrical connector, secure the coupler, remove valuable tools, and confirm that the trailer cannot roll or be easily moved. Do not leave the breakaway cable attached to a fixed object or the breakaway pin pulled. Check the trailer periodically throughout the winter instead of assuming that the setup will remain unchanged after wind, snow, ice, flooding, or temperature swings.
When spring arrives, remove covers and rodent traps, inspect for nests or wiring damage, reinstall and charge the batteries, set every tire to the specified cold pressure, verify wheel-nut and suspension torque using the correct specifications, check bearing or oil-hub condition, test the lights and brakes, operate the breakaway system, and cycle all ramps, jacks, hydraulic functions, and coupler latches before the first loaded trip.
If you’re not sure what axle rating, tire specification, hub system, or battery setup your trailer has, the team at Spencer Trailers can help identify it from the VIN, certification label, axle tag, or available build information. Stop by 291 West State Hwy 46 in Spencer or call or text (812) 829-0226.
Questions about what your specific trailer needs for storage? Reach out to us directly and we’ll point you in the right direction. Or if winter storage has you thinking it might be time to upgrade to a newer unit, check out our current inventory. Spring trade-in season starts faster than you’d think.
