HSE SOE/IRTE Recommended Coupling & Uncoupling Procedures for Standard Semi-Trailers
This procedure should be adopted whenever there is sufficient room between the tractor unit cab and the front of the trailer. Drivers must be aware of the risks involved when deviating from approved practices.
Coupling Procedure
- Reverse the tractor unit slowly in a straight line toward the trailer. Stop when the bottom of the fifth wheel ramps aligns with the front of the trailer.
- Apply the tractor unit parking brake, stop the engine, and remove the keys.
- Ensure the trailer parking brake is applied. Never walk under the trailer.
- Inspect the fifth wheel, locking devices, kingpin, and rubbing plate for damage. Do not proceed if any issues are found.
- Adjust the trailer coupling height to align correctly with the fifth wheel. This may involve adjusting landing legs or tractor air suspension.
- Reverse the tractor slowly until the fifth wheel jaws engage the kingpin.
- Apply the parking brake, stop the engine, and remove the keys again.
- Visually confirm the kingpin is locked in the jaws. Fit the safety ‘dog clip’ or similar device.
- Perform a ‘snatch test’ by selecting a low gear and gently pulling forward with trailer brakes applied. Repeat to confirm engagement.
- Connect the service (yellow) and electrical lines.
- Connect the emergency (red) air line and monitor for any trailer movement.
- If the trailer moves, disconnect immediately and confirm the trailer brake is applied.
- Raise landing legs and stow the handle. Release the trailer parking brake, check suspension ride height, and attach the number plate.
- Check all lamps and complete a full walk-around check, including load security and height indicator.
- Check that ABS/EBS lights function correctly during ignition and extinguish as expected.
Uncoupling Procedure
- Park in a straight line and apply the tractor unit parking brake, stop the engine, and remove the keys.
- Apply the trailer parking brake.
- Remove the trailer number plate and stow it.
- Lower the landing legs until they contact the ground.
- Disconnect all air and electrical lines. Grip the red line firmly as it may recoil with pressure.
- Secure connections in dummy holders or on the catwalk to prevent dirt ingress.
- Remove safety clip and release the fifth wheel handle.
- Slowly draw the unit forward by about 300mm. Apply the parking brake and lower air suspension to reduce 5th wheel pressure. Then pull away completely.
- Reset air suspension to ride height and perform a final walk-around of the trailer.
This guidance is based on the full HSE SOE/IRTE Code of Practice for Coupling, Uncoupling & Parking of Large Goods Vehicle Trailers. You can download the complete document from the related links section below.
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