Coupling, trailer handling and load security
Group T questions on coupling are procedural: the examiner wants the correct order, the checks that are easy to skip, and the weight arithmetic behind an overloaded trailer. Handling questions cover reversing with a trailer, cornering with a long assembly, parking on slopes and securing implements and loads.
Coupling sequence
- Park the trailer on firm, level ground, apply its parking brake and chock the wheels.
- Reverse the tractor slowly, guided by a spotter, and align the hitch.
- Engage the coupling, insert the pin and secure it with the clip; close and check the latch.
- Attach the secondary coupling or breakaway cable.
- Connect the brake line(s), check for leaks and confirm the trailer brakes release and apply.
- Connect the electrics and test lights, indicators and brake lights with a helper.
- Raise the jockey wheel, remove the chocks, then pull forward gently to confirm the coupling is locked.
Load and weight
Stay within the maximum authorised mass of the trailer, the permitted axle loads and the tractor's permitted towed mass. Put heavy items low and over the axle, keep the drawbar load within the permitted range, and secure everything with rated straps or chains - an implement resting on its own weight is not secured. Recheck lashings after the first few kilometres.
Worked example
A trailer's registration gives a maximum authorised mass of 3 500 kg and an unladen mass of 900 kg, so the payload is 2 600 kg. You load 2 900 kg of grain. Reasoning: the assembly is 300 kg over the authorised mass, which also stresses the tractor's permitted towed mass and the tyres. Remove 300 kg or split the load into a second trip; do not "balance" the excess by shifting it rearward, because that reduces drawbar load and makes the trailer unstable. Overloading also affects insurance cover after a claim.
Traps that cost marks
- Driving off without checking that the latch is locked and the pin clipped.
- Forgetting the breakaway cable or the trailer's own parking brake on a slope.
- Reversing a trailer without a spotter in a yard with people or machinery.
- Computing payload from the tractor's capacity instead of the trailer's documents.