Inspecting a combination vehicle
Section 6.5 of the Florida CDL Manual (p. 6-13) lists the extra checks for combination vehicles. It is tested on the Combination Vehicles test.
Key facts
| Part of | the Combination Vehicles test (80% to pass) | 49 CFR 383.135 |
|---|---|---|
| Manual section | §6.5 Inspecting a combination | FL CDL Manual p. 6-13 |
| Questions in CDL Mile's bank | 10 | CDL Mile, checked against FL CDL Manual |
Key rules
- § 6.5.1p. 6-13
The air-lines should be properly connected to the glad hands with no leaks. They should be secured but still have enough slack for turns, and be free of damage.
Additional Things to Check during a Walk-around Inspection
- § 6.5.2p. 6-14
Opening the emergency line valve at the back of the last trailer should release air. That shows air is reaching all the way back and the whole system is charged. Close the valve after the check.
Combination Vehicle Brake Check
- § 6.5.2p. 6-14
If no air comes out at the rear, check that the shut-off valves on the trailers and dollies are in the open position. Air has to reach the back for all the brakes to work.
Combination Vehicle Brake Check
Try two questions
Combination Vehicles · Inspecting a combination
Why does it matter that the tractor protection valve works correctly?
Tap an answer to see the explanation and the manual page.
Combination Vehicles · Inspecting a combination
You charged the trailer air brakes and the trailer rolls freely. You stop and pull out the trailer air supply control. What do you do next to check the trailer emergency brakes?
Tap an answer to see the explanation and the manual page.
More Combination Vehicles topics
Sources
Florida Commercial Driver's License Manual, version July 2022, Florida Department of Highway Safety and Motor Vehicles. Page references are to its printed page numbers. CDL Mile is independent and not affiliated with the FLHSMV.
Updated for the July 2022 Florida CDL manual. Last checked November 5, 2026.
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