Question of the Day:
When uncoupling twin trailers, first:
A. Release the dolly brakes
B. Disconnect the air and electric lines
C. Park the rig in a straight line on flat and solid ground.
According to the Utah Commercial Driver License Handbook, here is the order:
“Park rig in a straight line on firm level ground.
Apply parking brakes so rig won’t move.
Choke wheels of second trailer if it doesn’t have spring brakes.
Lower landing gear of second semitrailer enough to remove some weight from dolly.
Close air shut-offs at rear of first semitrailer (and on dolly if so needed.)
Disconnect all dolly air and electric lines and secure them.
Release dolly brakes.
Release converter dolly fifth wheel latch.
Slowly pull tractor, first semitrailer, and dolly forward to pull dolly out from under rear semitrailer.”
To Uncouple the Converter Dolly:
“Lower dolly landing gear.
Disconnect safety chains.
Apply converter gear spring brakes or chock wheels.
Release pintle hook on first semi-trailer.
Slowly pull clear of dolly.
Never unlock the pintle hook with the dolly still under the rear trailer. The dolly tow bar may fly up, possibly causing injury, and making it very difficult to re-couple.”
Utah Commercial Driver License Handbook, State of Utah Department of Public Safety Driver License Division. http://driverlicense.utah.gov, Section 7 – Doubles and Triples, page 7-2,3.
We hope this information and practice test questions are helpful. For a great truck driving school visit http://www.crengland.com/truckdrivingschools.com/index.jsp.