Review Questions - Click On The Picture To Begin...
- No more than 4 psi
- No more than 3 psi
- No more than 5 psi
- No more than 2 psi
Quote From The CDL Manual:
With the engine running, build the air pressure to governed cut-out (100-125 psi). Shut off the engine, turn the electrical power on, chock your wheels, if necessary, release the tractor protection valve and parking brake (push in), fully apply the foot brake and hold it for one minute. Check the air gauge to see if the air pressure drops more than 3 pounds in 1 minute (single vehicle) or 4 pounds in 1 minute (combination vehicle) with brake applied. When brake is unapplied, air pressure drops more than 2 pounds in 1 minute with a single vehicle and 3 pounds in 1 minute in a combination vehicle.
TruckingTruth's Advice:
Be sure to memorize how much air loss is acceptable when the service brakes are applied and not applied.
- High-beam headlights
- All of these things must be checked
- Brake lights
- Reflectors
Quote From The CDL Manual:
Lights/reflectors: Check that all external lights and reflective equipment are clean and functional. Light and reflector checks include:
- Clearance lights (red on rear, amber elsewhere)
- Headlights (high and low-beams); taillights
- Turn signals
- 4-way flashers
- Brake lights
- Red reflectors (on rear) and amber reflectors (elsewhere)
Note: Checks of brake turn signal and 4-way flasher functions must be done separately.
TruckingTruth's Advice:
While it may get a bit repetitive, during the pre-trip exam you need to point out and identify every light and reflector on both the truck and the trailer. Make sure all lights and reflectors are functioning properly, are clearly visible, properly mounted and secured, and not cracked or broken.
- Red on the front, amber elsewhere
- Red on the rear, amber elsewhere
- Red only
- Amber only
Quote From The CDL Manual:
Lights/reflectors: Check that all external lights and reflective equipment are clean and functional. Light and reflector checks include:
- Clearance lights (red on rear, amber elsewhere)
- Headlights (high and low-beams); taillights
- Turn signals
- 4-way flashers
- Brake lights
- Red reflectors (on rear) and amber reflectors (elsewhere)
Note: Checks of brake turn signal and 4-way flasher functions must be done separately.
- You will be docked 25 points
- Performing an air brake inspection is voluntary
- You will be reminded of the oversight
- You will receive an automatic failure
Quote From The CDL Manual:
Air brake check (air brake-equipped vehicles only): Failure to perform an air brake check will result in an automatic failure of the Vehicle Inspection Test.
TruckingTruth's Advice:
If you forget to perform an air brake check, you will be automatically disqualified and will need to retest. Further, the air brake check must be performed in a very specific order. If any step is done improperly or if you forget any step, that will also be grounds for disqualification. The proper steps to checking an air brake system is as follows:
- 1. With air pressure built up to 120 - 125 psi (fully charged system), depress the clutch and put the transmission into a low gear (keeping the transmission in gear will prevent the truck from rolling).
- 2. Shut the engine off, but turn the key back to the "on" position (this will allow you to hear the low air pressure warning alarm later in the test).
- 3. Release your foot off the clutch.
- 4. Release both the yellow tractor parking brake and the red trailer parking brake if equipped (remember, the truck is in gear so you won't roll - stay off the service brakes).
- 5. After air stabilizes (no sound of rushing air), fully apply the foot brake and hold it for one full minute (you can ask the examiner to time it for you). The system should not lose any more than 3 psi for a single vehicle and 4 psi for a combination vehicle in that minute. During this time, listen for any air leaks.
- 6. Begin "fanning" off the air pressure by rapidly pushing and releasing the foot brake. The low air warning light and buzzer should activate before pressure drops below 60psi.
- 7. Continue to fan the service brakes. At approximately 40 psi, the red tractor protection valve (trailer brakes) should pop out. Continue to fan off air pressure until the yellow tractor valve pops out (tractor brakes).
- 8. Put the transmission into neutral, depress the clutch, and restart the truck.
- No more than 5 psi
- No more than 4 psi
- No more than 3 psi
- No more than 6 psi
Quote From The CDL Manual:
With the engine running, build the air pressure to governed cut-out (100-125 psi). Shut off the engine, turn the electrical power on, chock your wheels, if necessary, release the tractor protection valve and parking brake (push in), fully apply the foot brake and hold it for one minute. Check the air gauge to see if the air pressure drops more than 3 pounds in 1 minute (single vehicle) or 4 pounds in 1 minute (combination vehicle) with brake applied. When brake is unapplied, air pressure drops more than 2 pounds in 1 minute with a single vehicle and 3 pounds in 1 minute in a combination vehicle.
TruckingTruth's Advice:
Be sure to memorize how much air loss is acceptable when the service brakes are applied and not applied.
- About 20 psi
- About 60 psi
- About 45 psi
- About 100 psi
Quote From The CDL Manual:
At about 40 psi on a tractor-trailer combination vehicle, the tractor protection valve and parking brake valve should close (pop out).
TruckingTruth's Advice:
Important things to memorize:
- The low air pressure warning device will activate before 60 psi.
- The tractor protection valve will close (when the valve pops out) at about 40 psi.
All combination trucks are a bit different. Sometimes both valves will pop out at the same time, but generally the tractor protection valve (the red knob) will pop out first. When performing your brake test, continue depleting air pressure until both the red and yellow valves pop out. If both valves have not closed (popped out) and your air pressure is below 20psi, there is a problem in your brake system.
- No more than 1 psi
- No more than 4 psi
- No more than 2 psi
- No more than 3 psi
Quote From The CDL Manual:
With the engine running, build the air pressure to governed cut-out (100-125 psi). Shut off the engine, turn the electrical power on, chock your wheels, if necessary, release the tractor protection valve and parking brake (push in), fully apply the foot brake and hold it for one minute. Check the air gauge to see if the air pressure drops more than 3 pounds in 1 minute (single vehicle) or 4 pounds in 1 minute (combination vehicle) with brake applied. When brake is unapplied, air pressure drops more than 2 pounds in 1 minute with a single vehicle and 3 pounds in 1 minute in a combination vehicle.
TruckingTruth's Advice:
Be sure to memorize how much air loss is acceptable when the service brakes are applied and not applied.
- Before pressure drops below 40 psi
- Before pressure drops below 80 psi
- Before pressure drops below 60 psi
- Before pressure drops below 20 psi
Quote From The CDL Manual:
Low-air warning devices (buzzer, light, flag) should activate before air pressure drops below 60 psi.
TruckingTruth's Advice:
The low-air warning should activate BEFORE 60psi. They are very picky with the wording on this. Don't say "about" 60 psi or "around" 60 psi, it must be "before" 60 psi.
- No more than 4 psi
- No more than 5 psi
- No more than 3 psi
- No more than 2 psi
Quote From The CDL Manual:
With the engine running, build the air pressure to governed cut-out (100-125 psi). Shut off the engine, turn the electrical power on, chock your wheels, if necessary, release the tractor protection valve and parking brake (push in), fully apply the foot brake and hold it for one minute. Check the air gauge to see if the air pressure drops more than 3 pounds in 1 minute (single vehicle) or 4 pounds in 1 minute (combination vehicle) with brake applied. When brake is unapplied, air pressure drops more than 2 pounds in 1 minute with a single vehicle and 3 pounds in 1 minute in a combination vehicle.
TruckingTruth's Advice:
Be sure to memorize how much air loss is acceptable when the service brakes are applied and not applied.
- Apply the parking brake only and make sure it will hold the vehicle by shifting into a low gear and gently pulling against the brake
- If the truck is equipped with a trailer hand valve, apply full pressure to the trailer service brakes then gently tug against the brakes in a low gear to be sure the brakes are functioning properly
- Bring the truck to approximately 20mph then apply the parking and emergency brakes to see if they are effective in stopping the truck
- Move forward in the lowest possible gear at idle speed, then apply the emergency brake and make sure you come to a full stop
Quote From The CDL Manual:
Parking brake check: Apply parking brake only and make sure it will hold the vehicle by shifting into a lower gear and gently pulling against the brake.
TruckingTruth's Advice:
To properly perform a parking break check, you must start the truck and build air to 120 to 125 psi. Place the transmission into a low gear. Release the yellow tractor park brake valve and do a light "tug" to be certain the trailer brakes hold the truck from rolling. Then, reverse the brake valves (set the tractor brakes and release the trailer brakes). Do a light tug again. The tractor brake should keep the truck from rolling. Here's what to say to the examiner:
"I will now perform a parking break check. I have a fully charged system and will check the trailer parking brakes first. [Do your trailer tug test here.] Now, I will check the tractor parking brakes. [Reverse the brakes and do your tractor tug test here.] Both the trailer parking brakes as well as the tractor parking brakes are functioning normally."