Emergency System Check. Turn electrical power on and begin fanning off the air pressure by rapidly applying and releasing the foot brake. Low air warning devices (buzzer, light, other) should activate before air pressure drops below 60 psi. Continue to fan off the air pressure. Normally within the range of 20-45 psi on a tractor-trailer combination vehicle, the tractor parking valve and parking brake valve should close (pop out). On other combination vehicle types and single vehicle types, the parking brake valve should close (pop out).
Power steering: With the engine running, check for excessive play by turning the steering wheel back and forth. Play should not exceed 10 degrees (or about 2 inches on a 20-inch wheel) before the front left wheel barely moves.
Trailer (if applicable): With the tractor parking brake released and the trailer parking brake engaged (combination vehicles only), check that the trailer parking brake will hold the vehicle by gently trying to pull forward with the trailer parking brake on.
The following items must be inspected on every tire:
Tread depth: Check for minimum tread depth (4/32 on steering axle tires and 2/32 on all other tires).
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 stems are not missing, broken or damaged.
Tire inflation: Check for proper inflation by using a tire gauge or a mallet. Note: You will not get credit if you simply kick the tires to check for proper inflation.
That there is no mismatch tires (size and construction).
Re-grooved or re-capped tires are not permitted on bus steer tires.
The The Pre-Trip Inspectin portion of the CDL Exam is required to obtain your CDL. During the pre-trip inspection, you must show that the vehicle is safe to drive. You may have to walk around the vehicle and point to or touch each item and explain to the examiner what you are checking and why. You will NOT have to crawl under the hood or under the vehicle.
Drivers need to have knowledge of how the actual vehicle(s) that they are conducting the test in operate. The drivers need to be able to explain and demonstrate different checks for the examiner as requested.
Taking the CDL Pre-trip Inspection Test
Class A Pre-trip Inspection Test
If you are applying for a Class A CDL, you will be required to perform a pre-trip inspection in the vehicle you have brought with you for testing. The vehicle must be a combination vehicle, representative of the unit you will be driving and must meet the class weight requirements. If the vehicle is an air brake vehicle, you must first pass the air brake knowledge test. You also must have passed all applicable endorsement knowledge tests that pertain to the vehicle you bring in for testing. Your test will require an inspection of the areas of the vehicle as instructed by your CDL examiner.
Class B and C Pre-trip Inspection Test
If you are applying for a Class B or C CDL, you will be required to perform a pre-trip inspection in the vehicle you have brought with you for testing. The vehicle must be a straight truck, passenger bus or school bus, representative of the vehicle you will be driving and must meet the class weight requirements. If the vehicle is an air brake vehicle, you must first pass the air brake knowledge test. You also must have passed all applicable endorsement knowledge tests that pertain to the vehicle you bring in for testing. Your test will require an inspection of the areas of the vehicle as instructed by your CDL examiner.
TruckingTruth's Pre-Trip Inspection Study Guide
We have an excellent Pre-trip Inspection Study Guide which includes a complete pre-trip inspection with photos and descriptions, numerous pre-trip inspection videos, and a complete vehicle checklist.