What is the blue air line on a tractor trailer?

Air and Electrical Lines The red line is the air line for the trailer’s emergency brake. The green line is the electrical line. The blue line is the air line for the trailer’s service brake. Connect these lines to the corresponding couplers and socket on the trailer before moving the trailer.

What color is the emergency air line?

color red
Emergency lines are often coded with the color red (red hose, red couplers, or other parts) to keep from getting them mixed up with the blue service line.

What are the airlines on a truck?

Modern trucks have two air lines which supply the trailer with air. The first is the supply air line (red) and the second is the service air line (yellow).

What are the blue and red Air Lines for?

Blue is used for the service lines and red for the emergency lines. If the driver were to cross the air lines, supply air would be sent to the service line instead of going to charge the trailer air tanks. Air would not be available to release the trailer spring brakes (parking brakes).

What is emergency air line for?

Emergency air line: The emergency line (also called the supply line) has two purposes: (1) To supply air to the trailer air tanks, and (2) to control the emergency brakes on combination vehicles. Loss of air pressure in the emergency line causes the trailer emergency brakes to come on.

What are the blue and red air lines for?

What is another name for the service line?

The service line, also called the control line or signal line, carries air to the trailer brakes and is controlled by the foot brake or trailer hand brake.

What is the purpose of the service line on a tractor trailer?

The service line (also called the control line or signal line) carries air which is controlled by the foot brake or the trailer hand brake. The pressure in the service line will similarly change depending on how hard you press the foot brake or hand valve.

Where are the Air Lines on a tractor?

Look for the air line couplers on the tractor and trailer. Two air lines extend from the back of the tractor — one is red and one is blue. Each line has a coupler on the end of it called a glad hand that mates with a corresponding glad hand on the front of the trailer.

How to hook up the air supply on a tractor trailer?

If any are cracked or missing, they must be replaced immediately. Connect the service line — the blue one – to the blue glad hand on the trailer by positioning the faces of the glad hands together and turning them clockwise until the grooves lock.

What are the Air Lines in a trailer?

Control or Service Line – The air lines in the trailer air brake system that perform the normal braking of the vehicle from the tractor foot valve or hand valve. Control or service lines are commonly associated

Why is the air supply on a tractor important?

by Jeff Miller. Of all of the systems on a tractor trailer, the air supply system is the most important because it controls the rig’s brakes. Every time a trailer is hooked to a tractor the air supply system must be hooked up by the operator.