D.O.T Inspection Procedure
This procedure helps ensure that your heavy-duty vehicles are in optimal condition and is also critical for the safety of everyone on the road.
Marion Ag Service
01/23/2025
D.O.T Inspection Procedure
This procedure helps ensure that your heavy-duty vehicles are in optimal condition and is also critical for the safety of everyone on the road.
Vehicle Type
1. Brake System
Fifth Wheels
(1) Mounting to frame (a) Any fasteners missing or ineffective (b) Any movement between mounting components c) Any mounting angle iron cracked or
Service Brakes
(1) Absence.; of braking action on any ax!e required to have brakes upon application of the service brakes (such as missing brakes or brake shoe(s) lading to move upon application of a wedge. S-cam, cam, or disc brake) (2) Missing or broken mechanical components, including shoes, lining, pads, springs, anchor pins, spiders, cam rollers, and pushrods, and air chamber mounting bolts. (3) Loose brake components, including air chambers, spiders, and camshaft support brackets. (4) Audible air leak at brake chamber (Example-ruptured diaphragm, loose chamber clamp, etc.) {5) Readjustment limits. (a) The maximum pushrod stroke must not be greater than the values given in the tables below and at §393 47 (e). Any brake stroke exceeding the readjustment limit will be rejected. Stroke must be measured with engine off and reservoir pressure of 80 to 90 psi with brakes fully applied (b) For actuator types not listed in these tables. the pushrod stroke must not be greater than 80 percent of the rated stroke marked on the actuator by the actuator manufacturer, or greater than the readjustment limit marked on the actuator by the actuator manufacturer (6) Brake linings or pads (a) The lining or pad is not firmly attached to the shoe (b) Saturated with oil, grease, or brake fluid; or 1c) Non-steering axles: Lining with a thickness less than 1/4 inch at the shoe center for air drum brakes. 1/16 inch or less at the shoe center for hydraulic and electric drum brakes, and less than 1/8 inch for air disc brakes (d) Steering axles: Lining with a thickness less than 1/4 inches at the shoe center for drum brakes. less than 1/8 inches for air disc brakes and 1/16 inch or less for hydraulic disc and electric brakes (7) Missing brake on any axle required to have brakes (8) Mismatch across any power unit steering axle of (a) Air chamber sizes (b) Slack adjuster length Wedge Brake Data.-Movement of the scribe mark on the lining shall not exceed 1/16 inch
Parking Brake System
No brakes on the vehicle or combination are applied upon actuation of the parking brake control, including driveline hand controlled parking brakes
Brake Drums or Rotors
(1) With any external crack or cracks that open upon brake application (do not confuse short hairline heat check cracks with flexural cracks). (2) Any portion of the drum or rotor missing or in danger of falling away
Brake Hose
( 1) Hose with any damage extending through the outer reinforcement ply. (Rubber-impregnated fabric cover is not a reinforcement ply). (Thermoplastic nylon may have braid reinforcement or color difference between the cover and inner tube. Exposure of the second color is a case for rejection.) (2) Bulge or swelling when air pressure is applied. (3) Any audible leaks (4) Two hoses improperly joined (such as a splice made by sliding the hose ends over a piece of tubing and clamping the hose to the tube) {5) Air hose cracked, broken, or crimped
Brake Tubing
( 1) Any audible leak (2) Tubing cracked, damaged by heat, broken, or crimped.
Low Pressure Warning System
The device is missing, inoperative, or does not operate at 55 psi and below. or 1/2 the governor cut-out pressure, whichever is less
Tractor Protection Valve
Inoperable or missing tractor protection valve(s) on power unit
Air Compressor
(1) Compressor drive belts in condition impending or probable failure (2) Loose compressor mounting bolts (3) Cracked, broken, or loose pulley {4) Cracked or broken mounting brackets, braces, or adapters
Electric Brakes
( 1) Absence of braking action on any wheel required to have brakes (2) Missing or inoperable breakaway braking device.
Hydraulic Brakes
(1) Master cylinder less than 1/4 full. (2) No pedal reserve with engine running except by pumping pedal (3) Power assist unit fails to operate (4) Seeping or swelling brake hose(s) under application of pressure (5) Missing or inoperative check valve (6) Has any visually observed leaking hydraulic fluid in the brake system (7) Has hydraulic hose(s) abraded (chafed) through outer cover-to·labric layer (8) Fluid lines or connections leaking restricted, crimped, cracked, or broken (9) Brake failure or low fluid warning light on and/or inoperative
Vacuum Systems
(1) Has insufficient vacuum reserve to permit one full brake application after the engine is shut off. (2) Has vacuum hose{s) or line(s) restricted, abraded {chafed) through the outer cover to cord ply. crimped, cracked. broken or has collapse of vacuum hose{s) when vacuum is applied (3) Lacks an 0perative low-vacuum warning device as required
Antilock Brake Systems
(I) Missing ABS malfunction indicator components (i.e., bulb. wiring. etc.). (2) ABS malfunction indicator that does not illuminate when power is first applied to the ABS controller {ECU) during the initial power-up. (3) ABS malfunction indicator that stays illuminated while power is continuously applied to the ABS controller (ECU) (4) ABS malfunction indicator lamp on a trailer or dolly does not cycle when electrical power is applied (a) only to the vehicle's constant ABS power circuit, or (b) only to the vehicle's stop lamp circuit. (5) With its brakes released and its ignition switch in the normal run position, power unit does not provide continuous electrical power to the ABS on any air-braked vehicle it is equipped to tow (6) Other misssing or inoperative ABS components.
Automatic Brake Adjusters
(1) Failure to maintain a brake within the brake stroke limit specified by the vehicle manufacturer (2) Any automatic brake adjuster that has been replaced with a manual adjuster. (3) Damaged, loose. or missing components (4) Any brake that is found to be out of adjustment on initial inspection must be evaluated to determine why the automatic brake adjuster is not functioning properly and the problem must be corrected in order for the vehicle to pass the inspection. It is not acceptable to manually adjust automatic brake adjusters without first correcting the underlying problem. For example, there may be other components within the braking system that are distressed or out of specification (i.e., broken welds. loose mounting hardware. cracked brake drums, worn bushings. etc.) that would require immediate attention.
2. Coupling Devices
Pintle Hooks
(1) Mounting to frame (a) Any missing or ineffective fasteners (a fastener is not considered missing if there is an empty hole in the device but no corresponding hole in the frame or vice versa) (b) Mounting surface cracks extending from point of attachment (e.g., cracks in the frame at mounting bolt holes). (c) Loose mounting (d) Frame cross member providing pintle hook attachment cracked. (2) Integrity (a) Cracks anywhere in the pintle hook assembly (b} Any welded repairs to the pintle hook. (c) Any part of the horn section reduced by more than 20%. (d) Latch insecure.
Drawbar/Towbar Eye
(1) Mounting. (a) Any cracks in attachment welds. (b) Any missing or ineffective fasteners. (2) Integrity. (a) Any cracks (b) Any part of the eye reduced by more than 20%
Drawbar/Towbar Tongue
(1) Slider (power or manual) (a) Ineffective latching mechanism (b) Missing or ineffective stop. (c) Movement of more than 1/4 inches between slider and housing. (d) Any leaking air or hydraulic cylinders, hoses or chambers (other than slight oil weeping normal with hydraulic seals/ (2) Integrity (a) Any cracks (b) Movement of 1/4 inch between the subframe and drawbar at the point of attachment.
Safety Devices
( 1) Safety devices missing (2) Unattached or incapable of secure attachment. (3) Chains and hooks. (a) Worn to the extent of a measurable reduction in link cross-section {b) Improper repairs including welding, wire, and small bolts. Rope and tape. (4) Cable (a) Kinked or broken cable strands (b) Improper clamps or clamping
Saddle-Mounts
(1) Method of attachment. (a) Any missing or ineffective fasteners (b) Loose mountings (c) Any cracks or breaks in a stress or load-bearing member. {d) Horizontal movement between upper and lower saddle-mount halves exceeds 1/4 inch.
3. Exhaust System
No leaks forward of/directly below the driver/sleeper compartment.
Any exhaust system determined to be leaking at a point forward of or directly below the driver/sleeper compartment.
Bus: No leaking/discharging in violation standard.
A bus exhaust system leaking or discharging to the atmosphere· (1) Gasoline powered-excess of 6 inches forward of the rearmost part of the bus. (2) Other than gasoline powered-in excess of 15 inches forward of the rearmost part of the bus (3) Other than gasoline-powered-forward of a door or window designed to be opened (exception: Emergency exits).
Unlikely to burn, char, or damage the electrical wiring, fuel supply, or any combustible part of the vehicle.
No part of the exhaust system of any motor vehicle shall be so located as would be likely to result in burning, charring, or damaging the electrical wiring, the fuel supply, or any combustible part of the motor vehicle.
4. Fuel System
No visible leak.
A fuel system with a visible leak at any point.
Fuel Tank Filler Cap
A fuel tank filler cap missing
Fuel tank securely attached.
A fuel tank not securely attached to the motor vehicle by reason of loose, broken or missing mounting bolts or brackets (some fuel tanks use springs or rubber bushings to permit movement)
5. Lighting Devices
All required lights/reflectors operable.
All lighting devices and reflectors required by Part 393 shall be operable.
6. Safe Loading
Vehicle parts, load, dunnage, spare tire, etc., secured.
(1) Part(s) of vehicle or condition of loading such that the spare tire or any part of the load or dunnage can fall onto the roadway. (2) Protection Against Shifting Cargo-Any vehicle without a front-end structure or equivalent device as required. (3) Container securement devices on intermodal equipment - All devices used to secure an intermodal container to a chassis, including rails or support frames, tiedown bolsters, locking pins, clevises, clamps, and hooks that are cracked, broken, loose, or missing.
Front End Structure
Intermodal Container Securement Devices
7. Steering Mechanism
Steering Wheel Free Play
a. Steering Wheel Free Play (on vehicles equipped with power steering the engine must be running}
Steering Column
(1) Any absence or looseness of U•bolt(s) or positioning part(s) (2) Worn, faulty, or obviously repair welded universal joint(s) (3) The steering wheel not properly secured
Front Axle Beam/All Other Steering Components
(1) Any crack(s). (2) Any obvious welded repair(s)
Steering Gear Box
(1) Any mounting bolt(s) loose or missing (2) Any crack(s) in gear box or mounting brackets.
Pitman Arm
Any looseness of the pitman arm on the steering gear output shaft?
Power Steering
Auxiliary power assist cylinder loose?
Ball and Socket Joints
(1) Any movement under steering load of a stud nut (2) Any motion, other than rotational between any linkage member and its attachment point of more than 1/4 inch.
Tie Rods and Drag Links
(1) Loose clamp(s) or clamp bolt(s) on tie rods or drag links (2) Any looseness in any threaded joint.
Nuts
Nuts. Nut(s) loose or missing on tie rods pitman arm, drag link, steering arm or tie rod arm.
Steering System
Any modification or other condition that interferes with free movement of any steering component.
8. Suspension
Axle Positioning Parts
Any U-bolt(s). spring hanger(s), or other axle positioning part(s} cracked. broken, loose or missing, resulting in shifting of an axle from its normal position. (After a turn, lateral axle displacement is normal with some suspensions. Forward or rearward operation in a straight line will cause the axle to return to alignment).
Spring Assembly
(1) Any leaves in a leaf spring assembly broken or missing. (2) Any broken main leaf in a leaf spring assembly. (This includes assembly with more than one main spring.) (3) Coil spring broken (d) Rubber spring missing. (5) One or more leaves displaced in a manner that could result in contact with a tire, rim, brake drum, or frame. (6) Broken torsion bar spring in a torsion bar suspension. (7) Deflated air suspension, i.e., system failure, leak, etc.
Torque, Radius or Tracking Components
Any part of a torque, radius or tracking component assembly or any part used for attaching the same to the vehicle frame or axle that is cracked, loose, broken or missing (Does not apply to loose bushings in torque or track rods.)
9. Frame
Frame Members
(1) Any cracked, broken, loose, or sagging frame member. (2) Any loose or missing fasteners, including fasteners attaching functional components such as the engine, transmission, steering gear, suspension, body parts and fifth wheel.
Tire and Wheel Clearance
Tire and Wheel Clearance Any condition. Including loading, which causes the body or frame to be in contact with a tire or any part of the wheel assemblies.
Adjustable Axle Assemblies (Sliding Subframes)
Adjustable Axle Assemblies (Sliding Subframes). Adjustable axle assembly with locking pins missing or not engaged.
10. Tires
Steer-Axle Tires
{1) With less than 4/32 inch tread when measured at any point on a major tread groove (2) Has body ply or belt material exposed through the tread or sidewall (3) Has any tread or sidewall separation (4) Has a cut where the ply or belt material is exposed (5) Labeled "Not for Highway Use' or displaying other markings which would exclude use on the steering axle (6) A tube-type radial tire without a radial tube stem markings. These markings include a red band around the tube stem, the word "radial" embossed in metal stems, or the word "radial" molded in rubber stems. (7) Mixing bias and radial tires on the same axle (8) Tire flap protrudes through valve slot in rim and touches stem (9) Regrooved tires except motor vehicles used solely in urban or suburban service (see exception 111 §393.751e) ( 10) Boot. blowout patch or other ply repair (11) Weight carried exceeds the tire load limit. This includes overloaded tires resulting from low air pressure (12) Tire is flat or has noticeable (e.g., can be heard or left) leak (13) Any bus equipped with recapped or retreaded tire(s). (14) So mounted or inflated that 11 comes in contact with any part of the vehicle
All Other Tires
(1) Weight carried exceeds tire toad limit. This includes overloaded tires resulting from low air pressure. (2) Tire is flat or has noticeable (e.g .. can be heard or felt) leak (3) Has body ply or belt material exposed through the tread or sidewall (4) Has any tread or sidewall separation (5) Has a cut where ply or belt material is exposed (6) So mounted or inflated that it comes in contact with any part of the vehicle. (This includes a tire that contacts its mate.) (7) is marked "Not for highway use" or otherwise marked and having like meaning (8) With less than 2/32 inch tread when measured at any point on a major tread groove
Speed-Restricted Tires
11. Wheel and Rims
Lock or Side Ring
Lock or Side Ring. Bent. broken, cracked improperly seated, sprung, or mismatched ring(s).
Wheels and Rims
Wheels and rims. Cracked or broken or has elongated bolt holes.
Fasteners
Fasteners (both spoke and disc wheels) Any loose, missing, broken, cracked, stripped or otherwise ineffective fasteners
Welds
(1) Any cracks in welds attaching the disc wheel disc to rim (2) Any crack in welds attaching tubeless demountable rim to adapter. (3) Any welded repair on aluminum wheel(s) on a steering axle. ( 4) Any welded repair other than disc to rim attachment on steel disc wheel(s) mounted on the steering axle
12. Windshield Glazing
No cracks, discoloration, obstacles, etc.
Windshield Glazing. (Not including a 2 inch border at the top, a 1-inch border at each side and the area below the topmost portion of the steering wheel.) Any crack, discoloration, or vision-reducing matter except (1) coloring or tinting applied at the time of manufacture. (2) any crack not over 1/4 inch wide, if not intersected by any other crack; (3) any damaged area not more than 3/4 inch in diameter, if not closer than 3 inches to any other such damaged area; (4) labels, stickers, decalcomania. etc (see §393.60 for exceptions)
13. Windshield Wipers
No missing, damaged, or inoperable wipes.
Windshield Wipers. Any power unit that has an inoperative wiper. or missing or damaged parts that render it ineffective
14. Motorcoach Seats
Seats securely fastened to the vehicle structure.
Any passenger seat that is not securely fastened to the vehicle structure.
15. Rear Impact Guard
In place, securely attached, proper size, proper placement.
a Trailers and semitrailers with a GVWR of 4.536 kg (10,001 lbs.) or more. manufactured on or after January 26. 1998 (see exceptions in Sec. 393.86/a)/1)). 1 Missing guard 2. Guard is not securely attached to trailer including broken or missing fasteners, any welds or parent metal cracked, or other damage that compromises secure attachment of the guard. 3. Guard horizontal member does not extend to within 100 mm (4 inches) of each. or extends beyond either, side extremity of the vehicle 4. Guard horizontal member is more than 560 mm (22 inches} above the ground. 5. Guard horizontal member is mo.e than 305 mm (12 inches) forward of the rear extremity of the vehicle 6. Guard horizontal member does not have a cross-sectional vertical height of at least 100 mm (4 inches) across its entire width b Commercial motor vehicles manufactured after December 31. 1952 (except /railers and semitrailers manufactured on or after Jan:.iary 26. 1998) (see exceptions in Sec. 393.86(b)(1) and Sec. 393 86/b)/3)/. 1. Missing guard 2. Guard is not securely attached to trailer by bolts, welding, or other comparable means 3. Guard horizontal member is more than 762 mm (30 inches) above the ground 4. Guard horizontal member does not extend to within 457 mm (18 inches) of each side extremity of the vehicle 5. Guard horizontal member is more than 610 mm (24 inches) forward of the rear extremity of the vehicle.
16. Other
List any other conditions which may prevent safe operation of this vehicle.
This vehicle has passed all the inspection items for the Annual Vehicle Inspection in accordance with 49 CFR part 396.
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Source: Marion Ag Service (Community Member)