Pre-Trip Inspection – Engine Compartment
These belts should not be frayed and should have no more than 3/4 inch of play.
What are the alternator, water pump, and air compressor belts?
Before starting your trip, make sure this device is working to alert others in case of an emergency.
What is the horn?
Every commercial vehicle must carry at least these three items for emergencies.
What are fire extinguisher, spare fuses, and reflective triangles?
What is the minimum Gross Vehicle Weight Rating (GVWR) for a vehicle that requires a Class B CDL?
26,001 pounds or more.
The air compressor governor controls:
When air is pumped into the air tanks (cut-in and cut-out pressure).
This fluid must be checked to ensure proper lubrication and prevent engine damage.
What is engine oil?
This gauge should build to at least 100–125 psi in vehicles with air brakes.
What is the air pressure gauge?
The fire extinguisher must be rated for this class of fires and be fully charged.
What is a 5 B:C or higher rating?
What is the maximum legal blood-alcohol concentration (BAC) for a CDL driver?
0.04%.
The air pressure should build from 85 to 100 psi within how many seconds?
45 seconds.
The alternator, air compressor, and water pump should all be securely mounted and not leaking this.
What is oil, coolant, or air?
These devices must work correctly to keep the windshield clear in bad weather.
What are the wipers and washers?
This document must always be in the vehicle and includes information about the last inspection.
What is the vehicle inspection report (DVIR)?
When approaching a railroad crossing, you should stop between what distances from the nearest rail?
15 to 50 feet.
What is the typical “cut-out” pressure when the governor stops the compressor?
Around 125 psi.
This part must be inspected for secure mounting and no visible leaks since it provides compressed air for the brakes.
What is the air compressor?
You test these lights to ensure they function before starting your route — both the red and amber ones.
What are the warning and indicator lights on the dashboard?
These should be checked to make sure all emergency exits open easily and latch securely.
What are the emergency windows and roof hatches?
If you are driving a heavy vehicle down a steep grade, what’s the safest way to control your speed?
Use a lower gear and apply the brakes intermittently (snub braking).
The “cut-in” pressure (when the governor turns the compressor back on) is usually around:
100 psi.
These should be tight and free of corrosion to ensure electrical systems work properly.
What are battery terminals and cables?
This control must function properly to ensure the parking brake holds the vehicle when engaged.
What is the parking brake (or hand brake) control?
You must inspect these to ensure they’re in place and that all passengers can access them quickly in an emergency.
What are seatbelts and safety restraints?
When starting a vehicle from a stop on a hill, you should:
Use the parking brake to hold the vehicle until the clutch engages.
The low air pressure warning must activate before the tank pressure drops below this value.
What is 60 psi?