Key Component Inspection Checklist
These key components must be thoroughly inspected during an annual trailer inspection.
Brake System
- Brake drums/rotors (cracks, wear, out-of-round)
- Brake lining/pads (thickness, contamination, secure)
- Brake camshafts, rollers, and S-cams (wear, seizure)
- Brake chambers (leaks, damage, proper size)
- Slack adjusters (free play, adjustment, wear)
- Pushrod travel (within specifications)
- Air lines and hoses (leaks, chafing, kinks)
- ABS system (functional, warning light operational)
- Spring brakes and emergency system (function test)
Suspension System
- Leaf springs (cracks, broken, shifted, missing)
- Air springs (leaks, damage, height control)
- Spring hangers and shackles (wear, cracks)
- U-bolts (tightness, cracks, missing)
- Torque arms and bushings (wear, damage)
- Axles (alignment, cracks, leaking seals)
- Radius rods and bushings (wear, damage)
- Air valves and height control (function, security)
Coupling Devices
- Kingpin (wear, cracks, deformation)
- Upper coupler plate (cracks, deformation, security)
- Kingpin mounting bolts (torque, security)
- Landing gear (operation, damage, security)
- Landing gear cross bracing (integrity, security)
- Landing gear mounting (security, cracks)
- Pintle hooks/eyes (wear, cracks) - if applicable
- Drawbar/tongue (bends, cracks) - if applicable
Frame and Structure
- Frame rails (cracks, bends, deformation)
- Cross members (cracks, missing, security)
- Floor (holes, structural integrity)
- Side rails/walls (damage, security)
- Roof structure (damage, leaks) - if applicable
- ICC bumper/underride guard (height, security)
- Welds and rivets (integrity, security)
- Sliding tandem assembly (lock pins, rails)
Wheels and Tires
- Tire tread depth (minimum 2/32" for all tires)
- Tire condition (cuts, bulges, separations)
- Tire inflation (proper pressure for all tires)
- Wheel/rim condition (cracks, bends, repairs)
- Lug nuts (all present, properly torqued)
- Wheel bearings (endplay, contamination)
- Hub oil seals (leaks, condition)
- Valve stems and caps (condition, present)
Lighting and Electrical
- Tail lights (operation, lens condition)
- Stop/brake lights (operation, lens condition)
- Turn signals (operation, lens condition)
- Clearance/marker lights (operation, lens condition)
- Reflectors and conspicuity tape (present, condition)
- License plate light (operation)
- ABS warning light (function test)
- Wiring harnesses (secure, no damaged insulation)
- 7-way connector (pins, corrosion, security)
Cargo Securement
- Anchor points (security, damage, deformation)
- Winches and tracks (operation, security)
- Cargo straps (damage, rating marks legible)
- Chains and binders (wear, damage, rating)
- Headboard/bulkhead (security, structural integrity)
- Stake pockets (deformation, security)
- Container locks (function, security) - if applicable
- E-track system (security, damage) - if applicable
Special Equipment
- Refrigeration unit (operation, mounting) - Reefers
- Hydraulic system (function, leaks) - Dumps/Lowboys
- Tailgate/doors (security, operation, seals)
- Tank integrity (welds, baffles, leaks) - Tankers
- Pressure relief devices (function) - Tankers
- Loading/unloading equipment (function, security)
- Liftgate (operation, hydraulics, security)
- Ramps and decks (security, condition)
Inspection Procedures
Follow these detailed procedures for specific components to ensure a thorough inspection.
Brake Measurement Procedure
- Measure brake drum diameter with a drum gauge tool
- Measure brake lining thickness at thinnest point
- Measure pushrod travel at 90-100 PSI with brakes applied
- Compare all measurements to manufacturer specs
- Check for proper brake adjustment
- Document all measurements for compliance records
Kingpin Inspection
- Use kingpin gauge to check for wear
- Inspect for elongation or mushrooming
- Check for cracks using appropriate methods
- Verify mounting bolts are secure and properly torqued
- Inspect upper coupler plate for cracks or deformation
- Measure relative to maximum allowable wear specs
Air Brake System Check
- Connect to tractor or test equipment
- Charge system to governor cutout pressure
- Check for leaks with soap solution at all connections
- Conduct applied leak test with brakes applied
- Verify proper operation of spring brakes
- Test ABS system with diagnostic equipment
Wheel Bearing Inspection
- Verify proper lubrication level in hubs
- Check for lubricant contamination
- Test for excessive endplay with dial indicator
- Raise axle and check for smooth rotation
- Listen for abnormal noise during rotation
- Inspect seals for damage or leakage
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