Dump Trailer Maintenance Checklist

A dump trailer needs two kinds of maintenance. The running gear (tires, wheels, bearings, brakes) needs the same care as any heavy trailer. The dump system (pivots, cylinder, pump, battery, gates) needs its own. The short version: check tires, lights, and lug nuts before every trip. Grease the pivots every month. Adjust the brakes every 3,000 miles. Repack the bearings every year.

The schedule below draws on the Dexter axle service manual (Dexter makes many of the axles under American dump trailers), the industry-standard dump trailer owner's manual, and 12-volt pump makers' instructions. Your trailer's manual and component labels come first. Where they disagree with this page, follow them.

New trailer break-in: the first 200 miles

The first few hundred miles matter more than people think. Wheels settle against the hubs, and brake shoes wear in fast.

• Lug nuts: Dexter says to torque wheel nuts before first use, then check and re-torque after the first 10, 25, and 50 miles. Repeat that sequence any time a wheel is removed, whether for a flat, a brake job, or new tires.
• Brakes: Dexter calls for brake adjustment at 200 miles and again at 3,000 miles on new axles. Self-adjusting brakes such as Dexter's Nev-R-Adjust don't need manual adjustment, but you should still check that they work.
• Brake controller: Set the gain in your truck to match the trailer once it's loaded, following the controller maker's directions.

What torque should lug nuts be?

Use the spec from your wheel manufacturer or trailer builder. Dexter's chart is a useful reference. It lists 100–120 ft-lb final torque for 14- to 16-inch wheels on 1/2-inch studs, and 140–170 ft-lb for 16-inch 8-lug wheels on 9/16-inch studs. Tighten in three stages in a star pattern. Dexter also lists the maximum safe torque for its grade 8 studs:

Going over these numbers can stretch studs and crack them later, so more torque is not safer. Make sure the lug nuts match the seat angle of your wheels (usually 60° or 90°).

Pre-trip checklist (every time you hook up)

This takes about five minutes. Do it every time.

Tire pressure gets its own line for a reason. Dexter's manual calls inflation pressure "the most important factor in tire life." Check it cold. A tire that has just been towed reads high, so don't let air out of a hot tire.

Weekly checklist (during regular use)

If the trailer works every day, do these once a week. If it sits for long stretches, do them before the first trip back.

• Tire pressure: Dexter recommends checking it weekly during use, even if you also check it before each trip.
• Walkaround for leaks: Look for wet spots or dust buildup under the hydraulic cylinder, at the hose fittings, and below the pump. A small weep at a fitting often becomes a hose failure later.
• Hoses: Check for chafing where hoses pass over frame edges or near the scissor arms.
• Wiring: Check the plug, the junction box, and any wiring that runs near the axles. Look for pinched or abraded spots.
• Gate hardware: Latches, pins, and hinges should move freely. Barn-door hold-backs should lock.
• Debris: Clean out material packed on top of the axles, behind the fenders, and in the corners of the bed. Wet dirt in those spots holds moisture against the steel.

Monthly checklist: grease points and the dump system

The industry-standard dump trailer owner's manual calls for greasing the dump body hinge and rear door hinges every month. Do the cylinder and scissor fittings at the same time.

Dump trailer grease points

Dexter's manual specifies a lithium complex, NLGI No. 2 grease with extreme-pressure (EP) additives for wheel bearings. A good EP lithium complex grease works well on the pivots too. Don't mix grease types. Dexter warns that lithium, calcium, sodium, and barium complex greases can be incompatible with each other.

Also check these monthly:

• Battery: Charge level (see the table below), terminal corrosion, and hold-down. If the trailer works daily, plug in the charger after each day's use, as the industry manual recommends.
• Hydraulic fluid condition: Clear and amber is good. Milky means water is in the fluid. Dark with grit means it's contaminated.
• Reservoir breather: Some pump makers have you clean the breather element. A clogged breather can starve the pump.
• Hinge pins and bushings: With the bed raised, look for side-to-side play at the rear hinge. Worn pins let the bed shift and wear the hinge ears out of round.

Measure with the battery at rest, after it has been off the charger and unused for a few hours. For more on pump and battery setups, see dump trailer hydraulics and batteries.

Every 3 months or 3,000 miles

These intervals come straight from Dexter's maintenance schedule:

• Brake adjustment: Adjust to proper running clearance. Skip this if you have self-adjusting brakes.
• Wheel nuts: Tighten to the specified torque.
• Tire condition: Look for cuts, uneven wear, and bulges. Uneven wear tells you something: center wear means overinflation, edge wear means underinflation, and side wear can mean overloading or a bent axle.
• Suspension wet bolts and equalizers: Grease them, if your suspension has grease fittings.

Every 6 months or 6,000 miles

• Brake magnets: Inspect for wear and check current draw. Dexter says to replace magnets in pairs (both sides of an axle) and to replace any magnet worn through to the coil.
• Brake controller: Check amperage output and modulation.
• Suspension parts: Look for bent hangers, loose fasteners, and worn bushings or spring eyes.
• Wheels: Look for cracks, dents, or distortion, especially after hitting a curb or a jobsite hole.
• Grease-zerk hubs: The industry-standard owner's manual calls for greasing zerk-equipped hubs every 6 months or 6,000 miles. Use a different color grease each time so you can see when fresh grease comes through.

Annual checklist (12 months or 12,000 miles)

This is the big service. Many owners do it before the busy season, often at a trailer shop.

Bearings: the zerk misconception

Dexter E-Z Lube axles have a grease fitting on the spindle end. Pumping grease in pushes it through the bearings. That's handy between services, but Dexter's guidance is clear: E-Z Lube bearings still need to be cleaned, inspected, and repacked every 12 months or 12,000 miles. You can't check a bearing cup for pitting or a seal for wear without pulling the hub. If a trailer sat in water or a hub was submerged, service those bearings right away.

Hydraulic fluid change interval

Pump makers set their own intervals. DLH Fluid Power, which makes 12-volt dump trailer power units, says to change the fluid after the first 100 hours of operation, then every 3,000 hours or 2 years. KTI Hydraulics recommends a premium anti-wear hydraulic oil and lists Dexron III ATF as acceptable under normal conditions. Whatever you use, don't mix types. Top off with the bed fully down so the cylinder's fluid is back in the tank.

Rust touch-up: a monthly habit, not an annual project

Dump trailers rust from the inside out. Wet material sits on the floor, gravel chips the paint off the sides, and road salt and magnesium chloride collect on top of crossmembers.

• Wash the bed and undercarriage after hauling salt, fertilizer, manure, or wet clay, and after driving on treated winter roads.
• Touch up chips while they're still small. Wire-brush to bright metal, prime, and topcoat.
• Don't pressure-wash the hydraulic power unit. DLH notes that its DC motor isn't sealed, and long moisture exposure causes early motor failure.
• Put dielectric grease on electrical connectors and battery terminals to slow corrosion.

We cover this in depth, including winter storage, in dump trailer rust prevention and storage.

Keep a log

Write down the date, the mileage or hours, and what you did. A cheap notebook in the truck works. A log helps you catch problems early (for example, a cylinder that needs topping off every month is leaking somewhere). It also helps when you sell. Buyers of used trailers look for maintenance records. See our used dump trailer inspection checklist for what they'll look at.

The bottom line

Most dump trailer failures start with skipped basics: loose lug nuts, dry bearings, a dead battery, or a pivot that never saw grease. Re-torque wheels at 10, 25, and 50 miles. Grease the pivots monthly with the empty bed on its prop. Adjust the brakes every 3,000 miles, and repack the bearings every year. Follow your trailer's and component makers' manuals first, and keep a log.