How To Link a Semi Trailer To a Tractor

1. The towing height, towing pin size, front turning radius, clearance radius, etc. of the semi trailer must match the towing vehicle, and inspection should be conducted before connection.

2. Carefully inspect the working surface of the tractor saddle and the traction pins and sliding plates of the semi-trailer for sand, dust, or other foreign objects, as well as sufficient lubricating grease.

3. Connection between towing vehicle saddle and towing pin

a. Adjust the support legs to match the height of the semi-trailer traction skateboard with the traction saddle. Generally, the position of the semi-trailer traction skateboard is 10 to 30mm lower than the center of the upper plane of the traction saddle of the tractor. Otherwise, sometimes it not only fails to connect, but also damages the traction seat, traction pin, and related parts.

b. Operate the locking mechanism of the traction seat (different from the traction seat, see the tractor user manual for details) to open the locking block and form a free state.

c. Check if the traction seat locking block has locked the traction pin and is securely locked.

d. Move the tractor forward slightly and check if the connection is in good condition.

4. Gas circuit connection

a. Connect the two air pipe joints (commonly known as handshake) on the tractor to the two air pipe joints on the semi trailer. At this point, the air supply pipeline of the tractor is connected to the air supply pipeline of the semi-trailer, and the control pipeline of the tractor is connected to the control pipeline of the semi-trailer (note the color of the connector: red represents the air supply pipeline, and blue represents the control pipeline).

b. After the air connectors are connected to each other, the disconnect switch of the semi trailer air circuit connection on the tractor should be turned on to make it in a ventilated state. Otherwise, the air supply to the semi trailer braking system cannot be supplied, and the braking system cannot function.

c. Start the engine, observe the air pressure gauge in the driver's cab, and increase the pressure in the air reservoirs of the tractor and semi-trailer to the specified pressure (usually 650-750kPa).

d. Check for air leaks in the air circuit and check if the braking system is working properly.

5. Connection of circuits

a. Insert the cable connection plug of the tractor into the cable connection socket at the front end of the box type semi-trailer.

b. Check if all electrodes are properly engaged, confirm if all lights are working properly, and replace the electrodes if necessary