HGV Trailer Coupling and Uncoupling Beginners Guide

If you are a new HGV driver and have been struggling to master HGV trailer coupling and uncoupling, no need to worry! We have put together this guide for beginner drivers in the UK. Follow these simple steps to make sure that you are on the right track while driving your truck.

HGV Trailer Coupling

HGV Trailer coupling

Step 1 Trailer Safety Check

Checking the trailer is very similar to completing your walk-around vehicle checks, checking lights, wheels, tyres, and overall condition. But before coupling your tractor unit to the trailer it is essential that you check the landing legs are not damaged in any way, and that the trailer parking brake is on.

If the parking brake was not engaged correctly then there is a risk of pushing the trailer backward as you reverse under it.

Step 2 Position Tractor Unit

Now that the trailer has been safety checked and the trailer brake is engaged, it is time to position your tractor unit.

Position the cab in front of the trailer allowing enough space to ensure that when looking in your mirrors you can easily see that the trailer is in line evenly on both sides.

Reverse the tractor unit backward towards the trailer looking in both mirrors to maintain alignment, at the point where the tractor unit is about to go under the trailer stop your vehicle.

From the outside of your tractor unit visually check that the height of the trailer is not set too high, as it could overshoot your 5th wheel and hit the cab.

If the height needs adjusting you can do this by setting the height of the tractor unit by using the air height adjustment control unit.

The ideal height is to ensure the tractor unit is going to slightly lift or take the weight of the trailer.

Step 3 Reverse and Engage Kingpin

Once you are happy with the height of the 5th wheel and trailer you can reverse the tractor unit under the trailer, you will feel the trailer lift or the tractor unit drop as it takes the weight, when you hear a solid click noise that will be the kingpin locking into place to the 5th wheel.

Once you have heard the click you need to do a tug test, put your truck into forward drive, and try to move forward slightly, if the kingpin is not engaged correctly the tractor unit will move from under the trailer, once you are happy that the vehicle is coupled to the trailer, visually check the locking mechanism and attach the dog clip safety chain to the locking handle.

Step 4 Connect Airlines and Electrics

The next step is to connect your airlines and electrics to the trailer ensuring they are all pushed into their sockets firmly and that the safety clips are fully engaged.

Step 5 Number Plate

One of the most common things that new drivers forget is the trailer number plate, it is important to ensure that the correct plate is corresponding with your tractor unit, put your trailer number plate into place on the trailer.

Step 6 Wind up Trailer Legs

Now that the number plate is fitted to the trailer it is time to wind up the landing legs, make sure they are fully raised as you could get fined if they are not fully lifted.

Step 7 Release Parking Brake

Now that the landing legs are lifted, it is safe to release the trailer parking brake, your tractor unit will now have full control over the trailer.

Uncoupling HGV Trailer

HGV Trailer Uncoupling

Step 1 Safe Parking

Before uncoupling a trailer from the tractor unit ensure that the ground is level and that the ground will support the landing legs of the trailer.

Step 2 Engage Trailer Brake

When you are happy the trailer is on firm ground, exit your vehicle and engage the trailer brake, this now ensures that the trailer cannot move in any way.

Step 3 Wind Down Trailer Legs

Once the trailer brake has been engaged you can now wind down the trailer legs so that they touch the floor then wind them back up 2 turns of the handle! the reason for this is when coupling a trailer you need to lift the trailer so winding the legs back up slightly ensures the trailer is not dropped too high and reduces any risk of damage to the landing legs.

Step 4 Remove Registration Plate

Once the landing legs are wound down to the correct position you can now remove the registration plate from the trailer, this is important to remember as your boss won’t be happy if you leave it on the trailer.

Step 5 Remove Air Lines and Electrics

Disconnect all connections from the trailer electrics, airlines, and EBS, make sure you secure them safely on the tractor unit, and don’t leave them trailing or in a tangled mess.

Step 6 Disengage 5th Wheel

The next step is to remove the safety chain dog clip from the release handle on the 5th wheel, pull the release handle so it locks into the out position.

Step 7 Remove Tractor Unit From Trailer

The last step is to drive your tractor unit from under the trailer slowly, just as you are about to drop the trailer pause to allow the air in the tractor units suspension to settle before pulling away from the trailer, pull away slowly and you feel the rear of your tractor unit raise slightly as it slowly drops the trailer fully onto its landing legs.

Video HGV Trailer Coupling and Uncoupling

Video Produced by 2 Start Ltd

Key Points to Remember

HGV Trailer Coupling

  • Trailer Safety Check
  • Position Tractor Unit
  • Reverse and Engage Kingpin
  • Connect Airlines and Electrics
  • Number Plate
  • Wind Up Trailer Legs
  • Release Trailer Parking Brake

HGV Trailer Uncoupling

  • Safe Parking
  • Engage Trailer Brake
  • Wind Down Trailer Legs
  • Remove Registration Plate
  • Remove Airlines and Electrics
  • Disengage 5th wheel
  • Remove Tractor Unit from Trailer

Frequently Asked Questions

Most frequent questions and answers

How do I hook up a trailer in the dark ?

Most tractor units have a rear cab light to see the trailer, if this is not operational and you have poor visibility you will need to reverse very slowly getting out of the cab to ensure you are in line, use a torch to help guide you, once you are in line move back slowly checking if necessary.

What can I do If the trailer has been dropped too high ?

If a trailer has been dropped too high you can try 2 things, if your tractor unit has an airbag lift, you can raise it up to attach the cab, if the trailer is still too high it will be necessary to lower it using the landing legs handle, this has 2 gear options to help this process.

What is the most important thing to remember when coupling up a trailer ?

It is important that the trailer brake is engaged before coupling up a trailer, if the brake was not engaged it is likely the tractor unit will push the trailer backwards which could cause damage or injury to somebody behind the trailer.

What can I do If the trailer has been dropped too low ?

Try lowering the cab using the rear airbag adjustment on the tractor unit, if it is still too low you will need to wind down the landing legs to raise the trailer, the landing legs handle has 2 gears to help with this. 

Safety is paramount when coupling or uncoupling a trailer

When coupling or uncoupling an HGV vehicle trailer, there are many safety considerations to take into account. If possible use a banksman, as this will save the driver getting in and out of the cab. However, even if a banksman is available, the driver should always check all aspects of the trailer safety procedures before proceeding.

Secondly, a driver could make use of a reversing camera which can be extremely helpful in seeing directly behind the cab.

Thirdly, when reversing, always go slowly and use gentle movements to avoid jerking the trailer and causing accidents, make sure that you are aware of your surroundings at all times and that you have good visibility before attempting to couple or uncouple an HGV vehicle trailer.

Finally, Always check that the trailer is properly secured before setting off.

Thank you for reading this British Trucking beginners guide “HGV Trailer Coupling and Uncoupling Beginners Guide” I hope you found it useful for coupling and uncoupling a trailer.