Coupling and uncoupling
Coupling and uncoupling trailers and semi-trailers
Safe coupling, lock test and correct uncoupling
Coupling and uncoupling is one of the manoeuvres where an overlooked detail can cause the load or the entire trailer to come loose. Follow the procedure in a fixed order, and always confirm the lock with a physical test before you drive.
Secure both vehicles first
Apply the parking brake on both the towing vehicle and the trailer/semi-trailer, and chock the wheels if necessary. Check that the coupling parts (ball/fifth wheel and drawbar eye/kingpin) are intact, clean and without excessive wear — look at wear marks and wear indicators.
Detachable coupling equipment must be correctly fitted and secured before you reverse.
Set the coupling height
Adjust the trailer's/semi-trailer's height so that the drawbar eye or kingpin meets the coupling/fifth wheel correctly when reversing. Coupling too high or too low can give a false lock that looks coupled but does not hold.
Reverse calmly up to the coupling
Reverse slowly and straight up to the coupling until it engages. With a semi-trailer, the kingpin must slide into the fifth wheel so the locking jaws close around it. Use the mirrors and possibly a helper — stop if anything binds.
Confirm the lock visually
Get out and visually check that the coupling is fully closed: locking handle/indicator in the locked position, no visible gap between the fifth wheel and the trailer plate, safety pin or bolt in place.
A coupling that »looks coupled« is not enough — it must be confirmed both visually and with a tug test.
Do a pull test
With the trailer's/semi-trailer's brake applied, pull forward gently. The vehicle must stay firmly coupled without coming loose. If it fails, the coupling is not engaged — recouple.
Connect brake, supply and electrics
Connect the brake and supply lines (typically the yellow control line and red supply line) and the electrical connector. Check that no air is leaking and that the lines and cable cannot get trapped or drag on the road.
Raise the landing legs and release the brakes
Raise the semi-trailer's landing legs fully and secure the crank/handle. Release the trailer's parking brake, remove the wheel chocks, and check that the lights and brakes on the trailer work before you drive off.
Uncoupling in reverse order
When uncoupling: park on level ground, apply the brakes, chock the wheels, lower the landing legs so they bear the load, shut off the air and disconnect the lines and electrics. Unlock the coupling, and only drive forward slowly once you have confirmed that the trailer is standing stable and supported.
Always lower the landing legs so that they bear the load BEFORE you unlock — otherwise the semi-trailer may tip.
Source
Based on Færdselsstyrelsen's syllabus for category C/E (clutch, wear check) and general driver practice.
Videos from NDLA
Video guide· Norwegian speech
Transport: Koble fra semitrailer
Source
NDLA
«Transport: Koble fra semitrailer» · Photographer: Tom Knudsen
License: CC BY-ND 4.0 · Original at NDLA ↗
Shown unaltered in the original language with the source's own subtitles. The video shows Norwegian practice — the method is often the same, but rules and standards may differ from the Danish ones.
May not be adapted: the licence only allows the video to be shown unchanged, so it is neither dubbed, cut nor translated.