Tractor-trailer and semi-trailer connection precautions

The connection between the fifth wheel and the traction pin.

The fifth wheel and kingpin are key components that bear the force of the semi-trailer connection. They are subject to multidimensional spatial torque, alternating loads, and dynamic impact forces during vehicle operation. The force system is complex and requires high usage requirements.

Before coupling, carefully check if there is sufficient lubricating grease on the fifth wheel surface of the tractor. Also, inspect the fifth wheel coupling pin and slide plate of the semi-trailer for any foreign objects and ensure the slide plate is clean.

Adjust the support legs to align the height of the semi-trailer's fifth wheel slide plate with the tractor's fifth wheel, typically positioning the semi-trailer's slide plate 1-3 centimeters lower than the center of the tractor's fifth wheel upper surface. Be cautious not to set it too high. Otherwise, it may not only prevent proper coupling but also cause damage to the fifth wheel coupling, kingpin, and related components.

Manipulate the traction seat locking mechanism to release the locking block and put it in a free state.

When the tractor is reversing, it is important to keep the centerline of the tractor aligned with the centerline of the semi-trailer, with a maximum allowable deviation of 40 mm. Align the tractor's fifth wheel with the kingpin of the semi-trailer, and slowly reverse until you hear a "click" sound indicating that the locking block has engaged and the tractor and semi-trailer are successfully coupled.

Check if the locking block of the traction seat is engaged with the traction pin and if it is securely locked.

Drive the tractor forward and check if the connection is good.

Electrical circuit connection between the tractor and the semi-trailer

In addition to the connection between the fifth wheel and the traction pin, the electrical connection between the tractor and the semi-trailer is also very important.

Connect the two air hose couplings from the tractor to the corresponding couplings on the semi-trailer. This will connect the air supply line of the tractor to the air supply line of the semi-trailer, and the control line of the tractor to the control line of the semi-trailer (pay attention to the color of the couplings: install couplings with the same color together and avoid installing them in reverse).

After the air couplings are connected to each other, the air line connection release switch on the tractor must be turned open to allow air flow, otherwise air cannot be supplied to the semi-trailer braking system and the braking system will not work.

Start the engine, observe the air pressure gauge in the cab, and raise the pressure in the storage cylinder of the tractor and semi-trailer to the specified pressure.

Check the air circuit for air leakage and check whether the braking system is working properly.

Insert the cable connection plug of the tractor into the seven-hole socket on the front of the semi-trailer until it clicks into place on the block of the seven-hole plug.

Check whether the electrodes are well connected, and confirm whether the lights such as side lights and tail lights are working properly.

When transporting goods with a semi-trailer, friends driving trucks must check the connection between the tractor and the semi-trailer in all aspects to prevent any loose connections and avoid accidents. Wishing all truck drivers a safe journey.