Enclosed Trailer Maintenance Guide: Checklist & Service Schedule
Regular inspections and preventive maintenance can help your enclosed trailer stay safer, last longer and avoid unexpected problems on the road.
Better Trailers Since 2007
An enclosed trailer is an investment, and regular maintenance can help protect that investment.
Trailer tires, brakes, wheel bearings, suspension components, lights, couplers, safety chains, doors and seals all experience wear. A trailer that sits for long periods can require attention too, particularly its tires, battery, electrical connections and exposed metal components.
Whether you use your trailer every day for work or only occasionally for motorcycles, ATVs, cars or recreational equipment, establishing a regular inspection routine can help identify problems before they become expensive repairs or roadside breakdowns.
This Southern Trailer Depot guide covers the major areas every enclosed trailer owner should monitor.
Maintenance intervals vary by trailer and component manufacturer.
The information in this guide is intended as general guidance. Always follow the maintenance, inspection, torque, lubrication and replacement requirements specified by your trailer, axle, brake, tire, wheel, coupler and component manufacturers.
For example, Dexter's published schedule recommends checking brakes and the breakaway system at every use, wheel-nut torque at 3 months/3,000 miles, certain suspension and brake components at 6 months/6,000 miles, and wheel bearings and several brake components at 12 months/12,000 miles.
Enclosed Trailer Maintenance Schedule
Use this schedule as a convenient reminder of the systems that should be inspected regularly. Exact service intervals depend on the trailer's components, mileage, operating conditions and manufacturer requirements.
Trailers subjected to heavy commercial use, frequent long-distance towing, water, road salt, dirt roads or unusually heavy loads may require more frequent inspection and maintenance.
Before Every Trip: Trailer Safety Inspection
Before pulling onto the road, take a few minutes to walk around your trailer.
Check:
- Tires and visible tire condition
- Tire inflation
- Wheel and lug-nut condition
- Coupler connection
- Hitch and hitch ball
- Safety chains
- Breakaway cable
- Breakaway system
- Trailer electrical connector
- Running lights
- Brake lights
- Turn signals
- Trailer brakes
- Doors and latches
- Ramp door
- Cargo tie-downs
- Jack position
- Cargo security
Dexter specifically lists brake operation, breakaway-system function and tire inflation among its every-use checks.
A two-minute walk-around can catch a problem before it becomes a roadside problem.
Trailer Tire Maintenance
Trailer tires carry substantial loads and should receive attention before every trip.
Check for:
- Proper inflation
- Uneven tread wear
- Cracking
- Cuts
- Bulges
- Punctures
- Sidewall damage
- Embedded objects
- Valve-stem damage
- Signs of aging
- Proper load rating
NHTSA emphasizes proper tire inflation and recommends routinely checking tires for damage. Tire pressure should be checked when tires are cold for the most accurate reading.
Don't Forget the Spare
A spare tire isn't useful if it is flat when you need it.
Periodically inspect:
- Spare-tire pressure
- Tread and sidewall condition
- Mounting hardware
- Spare-tire carrier
- Accessibility
Wheel Lug Nuts
Loose wheel fasteners can cause serious damage.
Inspect your wheels and make sure the lug nuts are tightened according to the wheel, hub or trailer manufacturer's specified torque and tightening sequence.
Dexter's current maintenance schedule calls for wheel nuts and bolts to be tightened to specified torque values at its 3-month/3,000-mile interval.
Always use the manufacturer's specified torque.
Wheel Bearings & Hubs
Wheel bearings allow the trailer wheels to rotate smoothly while carrying significant loads.
Neglected bearings can lead to:
- Excessive heat
- Premature wear
- Hub damage
- Seal failure
- Wheel problems
- Roadside breakdowns
Inspect wheel bearings according to the axle manufacturer's recommendations.
For Dexter light-duty running gear, its published guidance calls for wheel bearings and cups to be inspected for corrosion or wear, cleaned and repacked at 12 months or 12,000 miles.
Warning Signs to Watch For
- Unusual wheel or hub noise
- Excessive play
- Grease leaking around the hub
- Unusual heat
- Rough wheel rotation
- Damaged grease seals
Trailer Brake Maintenance
Trailer brakes are one of the most important components on a loaded trailer.
Depending on the trailer, brake maintenance can involve:
- Testing brake operation
- Inspecting brake linings
- Checking brake magnets
- Inspecting wiring
- Checking brake adjustment
- Inspecting drums
- Inspecting electrical connections
- Testing the tow vehicle's brake controller
Dexter recommends testing brake operation at every use and includes additional brake inspections at mileage/time intervals in its maintenance schedule.
Possible Signs of Brake Problems
- Trailer pulling while braking
- Weak braking
- Delayed braking
- Unusual noises
- Excessive brake-controller output required
- Intermittent brake operation
- Wheel or hub overheating
Important
Trailer brake specifications and adjustment procedures vary. Follow the brake and axle manufacturer's instructions or have the system inspected by a qualified trailer service provider.
Breakaway System & Battery
The trailer breakaway system is designed to activate the trailer brakes if the trailer separates from the tow vehicle.
Regularly inspect:
- Breakaway switch
- Pull cable
- Wiring
- Battery
- Battery connections
- Battery charge
- Mounting hardware
Dexter lists checking breakaway battery charge and switch operation as an every-use inspection.
Check your breakaway system before towing.
Axles & Suspension
The axle and suspension system supports the trailer and cargo while absorbing road forces.
Depending on the trailer, components may include:
- Leaf springs
- Torsion axles
- Equalizers
- Shackles
- Bushings
- Hangers
- U-bolts
- Wet bolts
- Mounting hardware
Inspect For:
- Bent components
- Loose hardware
- Broken springs
- Worn bushings
- Damaged hangers
- Uneven tire wear
- Cracks
- Abnormal axle position
- Excessive corrosion
Dexter's schedule includes suspension inspections and lubrication at varying intervals depending on the component.
Trailer Lights & Electrical Wiring
Before towing, confirm that all required lights operate correctly.
Check:
- Tail lights
- Brake lights
- Turn signals
- Clearance lights
- Marker lights
- License-plate light
- Exterior loading lights
- Interior lights
- Trailer plug
- Wiring connections
Look for:
- Loose connections
- Exposed wires
- Corrosion
- Damaged connectors
- Moisture intrusion
- Broken lenses
NHTSA notes that compliant trailers are required to have appropriate safety components including lighting, tires and wheels.
Coupler, Safety Chains & Trailer Jack
Inspect the connection between your trailer and tow vehicle before every trip.
Coupler
Check for:
- Proper operation
- Secure connection
- Damage
- Excessive wear
- Rust
- Correct hitch-ball size
- Secure latch
Safety Chains
Inspect for:
- Bent or damaged hooks
- Excessive wear
- Cracks
- Damaged links
- Secure attachment points
Trailer Jack
Inspect:
- Mounting hardware
- Crank/electric operation
- Foot or wheel
- Lubrication where specified
- Electrical connections on electric jacks
Ramp Door, Side Door & Hinges
Trailer doors are used constantly and can loosen or wear over time.
Inspect:
- Hinges
- Latches
- Locks
- Door seals
- Ramp springs
- Cables
- Fasteners
- Transition flap
- Door alignment
- Weather stripping
Lubricate moving components where recommended by the manufacturer.
If a ramp door becomes unusually heavy or difficult to operate, have its spring-assist system inspected rather than attempting to repair a high-tension spring without appropriate knowledge and equipment.
Roof, Seams & Water Leaks
Water intrusion can damage:
- Plywood
- Flooring
- Walls
- Insulation
- Electrical components
- Cabinets
- Cargo
Regularly inspect the trailer roof and exterior seams.
Look For:
- Cracked sealant
- Loose trim
- Roof damage
- Gaps around vents
- Gaps around air conditioners
- Damaged door seals
- Water stains
- Soft plywood
- Interior discoloration
Pay Particular Attention To:
- Roof edges
- Front and rear roof seams
- Roof vents
- Air-conditioning openings
- Windows
- Exterior lights
- Doors
Trailer Floor & Interior
Trailer floors take considerable abuse from:
- Vehicles
- Motorcycles
- Equipment
- Water
- Mud
- Chemicals
- Tools
- Cargo
Inspect For:
- Soft areas
- Cracks
- Water damage
- Loose fasteners
- Damaged flooring
- Oil or chemical contamination
- Loose E-track
- Damaged D-rings
For Finished Trailers
Also inspect:
- Cabinets
- Countertops
- Electrical outlets
- Interior lighting
- Air conditioner
- E-track
- Appliances
- Generator compartments
- Interior wall panels
Preventing Rust & Corrosion
Road grime, moisture and road salt can accelerate corrosion.
Recommended Practices
- Keep the trailer clean
- Wash the undercarriage when exposed to road salt
- Inspect exposed steel
- Repair damaged protective coatings
- Keep electrical connectors clean
- Inspect fasteners
- Address surface rust before it spreads
- Keep drain areas clear
Pay particular attention to trailers frequently used near saltwater or in winter road conditions.
Storing an Enclosed Trailer
A trailer may accumulate maintenance problems even when it isn't moving.
Before long-term storage:
- Clean the trailer
- Remove moisture
- Inspect the roof
- Check tire pressure
- Inspect tires
- Protect the electrical connector
- Charge/maintain applicable batteries
- Secure doors
- Remove perishable cargo
- Store in a well-drained location
- Follow tire and axle manufacturer storage recommendations
Before returning the trailer to service, perform a complete pre-trip inspection.
When Should You Have Your Trailer Professionally Inspected?
Consider professional inspection when:
- Brakes aren't operating normally
- A wheel or hub becomes unusually hot
- Tires show abnormal wear
- The trailer pulls or tracks incorrectly
- You discover suspension damage
- A wheel has excessive movement
- Electrical problems continue after basic troubleshooting
- The trailer has been involved in an accident
- Structural damage is visible
- You're uncertain about the condition of a safety-critical component
Don't ignore a change in how your trailer sounds, handles or brakes.
Frequently Asked Questions
How often should I service my enclosed trailer?
There isn't one universal interval for every trailer. Service schedules depend on the axle, brakes, bearings, suspension and other components. Follow the manufacturers' specified time and mileage intervals.
How often should trailer wheel bearings be repacked?
Follow your axle manufacturer's requirements. As one example, Dexter recommends inspection, cleaning and repacking of applicable wheel bearings at 12 months or 12,000 miles in its light-duty maintenance guidance.
Should I check trailer tires before every trip?
Yes. Tire condition and inflation deserve frequent attention. Dexter lists tire inflation as an every-use check, while NHTSA emphasizes routine cold-pressure checks and inspections for tire damage.
How do I know what PSI to put in my trailer tires?
Follow the specifications provided for the particular trailer/tire application and its certification information rather than guessing based on another trailer.
How often should trailer brakes be inspected?
Follow the brake and axle manufacturer's schedule. Dexter calls for an operational brake test at every use and more detailed brake-component inspections at specified mileage/time intervals.
Why are my trailer tires wearing unevenly?
Possible causes include inflation problems, loading, wheel or suspension issues, axle alignment or damaged components. Uneven wear should be investigated rather than simply replacing the tire.
Do enclosed trailers require maintenance if they aren't used often?
Yes. Tires can lose pressure and age, batteries can discharge, corrosion can develop, seals can deteriorate and moisture can enter while a trailer sits.
Keep Your Trailer Ready for the Road
Whether you're hauling equipment to a jobsite, taking motorcycles on a trip, transporting a race car or using your enclosed trailer every day for business, regular maintenance helps protect your trailer and your investment.
Southern Trailer Depot has been helping customers find the right trailers since 2007.