Check that trailer air connectors are sealed and in good condition.
Make sure glad hands are locked in place, free of damage or air leaks.
Make sure the trailer electrical plug is firmly seated and locked in place.
Header Board
If equipped, check the header board to see that it is secure, free of damage, and strong enough to contain cargo.
If equipped, the canvas or tarp carrier must be mounted and fastened securely.
On enclosed trailers, check the front area for signs of damage such as cracks, bulges, or holes.
Side of Trailer
Landing Gear
Check that the landing gear is fully raised
Check that the crank handle is securely stowed
Make sure the support frame and gear are not damaged or missing parts.
If power operated, check for air or hydraulic leaks.
Reflectors/Reflector Tape (Sides)
Check to make sure the side of the trailer is equipped with reflective DOT tape
Make sure the tape and any reflectors are clean and securely fastened
Doors/Ties/Lifts
If equipped, check that doors are not damaged. Check that doors open, close, and latch properly from the outside.
Check that tie downs, straps, chains, and binders are secure.
If equipped with a cargo lift, look for leaking, damaged or missing parts and explain how it should be checked for correct operation.
Lift should be fully retracted and latched securely.
Frame
Look for cracks, broken welds, holes or other damage to the frame, cross members, box, and floor.
Tandem Release Arm/Locking Pins
Sliding mechanism and locking pins for sliding tandem axles on trailers.
If equipped, make sure the locking pins are locked in place and release arm is secured.
Remainder of Trailer
Inspect the wheels, suspension system, brakes, doors, ties, lift, and mud flaps per the procedures described in earlier lessons. The rear of the truck or trailer has some components that are not found on the front, or, the criteria is different. On the rear of the truck/trailer, you should inspect:
Rear Axle (Truck or Trailer)
Springs
Look for missing, shifted, cracked, or broken leaf springs.
Look for broken or distorted coil springs.
Torque Arm
The torque arm is a suspension member intended to control wheel motion in the longitudinal (fore-aft) plane. The link is connected (with a rubber or solid bushing) on one end to the wheel carrier or axle, on the other to the chassis of the vehicle. Torque Arms typically are mounted ahead of the wheel. In that position, they resist dive under braking forces and wheel hop under acceleration. The torque arm is also a means for adjusting the axle and keeps it from shifting and moving. Other common names are torsion bars, torque springs.
Check that the torque arm is not bent or damaged
Check for worn or missing bushings.
Check to see the torque arm is securely mounted.
U-Bolts
Check for broken, missing, or loose U-bolts.
Spring Mounts
Check for cracked or broken spring hangars
Check to see that spring hangars are securely mounted to the vehicle/trailer frame.
Air Bags
Air Bags act as springs or accompany them as a part of the vehicle or trailer suspension. Like springs, air bags dampen the wheel vibration caused by rolling over the road surface. If they become damage or leak, the weight of the load can shift causing a loss of control or allow the frame to come in contact with the tire causing a blowout.
Check air-ride suspension for damage and leaks.
Check air bag mounts (bolts) are in place and not damaged.
Shock Absorber
Check to see that shocks are secure and not leaking.
Slack Adjuster and Pushrod
Check that slack adjuster is securely mounted.
Check slack adjuster and pushrod for bent, broken, loose, or missing parts.
If the brakes are released and you pull the slack adjuster by hand, the pushrod slack should not exceed approximately one (1) inch, or with the brakes set, the angle formed between the pushrod and the slack adjuster should not exceed 90⁰ (rule of thumb- varies with different vehicles).
Brake Chamber
Check to see that brake chambers are not leaking, cracked or dented, and are mounted securely.
Make sure there are no loose or missing clamps.
Brake Hoses/Lines
Check that hoses or lines can supply air or hydraulic fluid to brakes.
Check for cracked, worn or frayed hoses, and that all couplings and fittings are secure and not leaking.
Fluid/Grease on Brake Components
Check brake drums/rotors and linings/pads for contaminants such as grease, oil, etc.
Brake Drum or Rotor
Check brake drums or rotors for cracks, dents, or holes. Also checks for loose or missing bolts.
Brake Linings or Pads
Check that brake linings or disk pads (where visible) are not worn dangerously thin. Know the minimum thickness for disk pads or linings for your vehicle.
Check that brake linings or disk pads are not cracked or damaged.
Measuring Tire Tread with a Coin
Tires
Tire Inflation: check for proper inflation by using a tire gauge. Note: You will not get credit if you simply kick the tires to check for proper inflation.
Tread depth: Check for minimum tread depth of 2/32” on rear axles of truck and trailer.
Tire condition: Check that tread is evenly worn and look for cuts or other damage to tread or sidewalls. Also, make sure that valve caps and stem are not missing, broken, or damaged.
Rims
Check rims for:
Damage or bent rims
Bent flange
No welding repairs
Rust trails that may indicate rim is loose on wheel.
Lug Nuts
Check that:
All lug nuts are present.
Lug nuts are tight.
No rust trails around nuts
There are no cracks radiating from lug bolt holes or distortion of the bolt holes.
Hub Oil Seal
Seals for axle/wheel assembly lubrication. Bearing seizure and uneven braking may result from lack of lubrication.
Check to see that hub oil/grease seals are not leaking, and if a sight glass is present, that the oil level is adequate.
Check to see hub cap is not cracked or damaged.
Check Axle seals on drive wheels to make sure they are not leaking
Spacers or Space
Check to see that spacers are not bent, damaged, or rusted through.
Check to see that spacers should be evenly centered with dual wheels and tires evenly separated.
Check for debris between the tires and make sure they are not touching.
When you have completed the outside inspection, complete the next lesson procedures for the in-cab checks, lighting, and brake tests.
.png)
