Perform the complying with checks in addition to ar 5.3: Inspecting air Brake Systems

Check the brakes top top a twin or triple trailer together you would certainly any combination vehicle. Ar 6.2 describes how to inspect air brakes on combination vehicles. You additionally must make the adhering to checks ~ above your dual or triple trailers:

Check air flow to every trailers:
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Use the tractor parking brake and also or chock the wheel to host the vehicle. Wait for air push to with normal, then press in the red “trailer air supply” knob. This will certainly supply air to the emergency (supply) lines. Use the trailer handbrake to administer air to the organization line. Walk to the rear of the rig. Open the emergency heat shut-off valve at the rear of the critical trailer. You have to hear air escaping, reflecting the entire system is charged. Nearby the emergency line valve. Open the business line valve to inspect that organization pressure goes with all the trailers (this check assumes that the trailer handbrake or the organization brake pedal is on), climate close the valve. If you carry out NOT hear waiting escaping native both lines, examine that the shut-off valves on the trailer(s) and also dolly (5) space in the open up position. Friend MUST have air all the method to the earlier for every the brakes to work.

You are watching: Which shut-off valves should be open and which closed?

Test tractor defense valve:

Charge the trailer waiting brake system, (i.e., construct up normal air pressure and also push the “air supply” knob in). Shut the engine off. Action on and off the brake pedal numerous times to minimize the air pressure in the tanks. The trailer waiting supply regulate (also called the tractor protection valve control) should pop out (or walk from “normal” come “emergency” position) as soon as the waiting pressure drops into the pressure variety specified by the manufacturer (usually in ~ the range of 20 come 45 psi).

Test trailer emergency brakes:

If the tractor security valve walk not occupational correctly, an air hose or trailer brake leak could drain every the air from the tractor. This would cause the emergency brakes to come on, with feasible loss the control.

Test trailer business brakes:
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Charge the trailer waiting brake system and check the the trailer rolfes freely. Then stop and pull the end the trailer air supply regulate (also called tractor protection valve regulate or trailer emergency valve) or place it in the “emergency” position. Pull gently top top the trailer through the tractor to inspect that the trailer emergency brakes space on.

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Check for common air pressure, relax the parking brakes, move the car forward slowly, and apply trailer brakes v the hand control (trolley valve), if for this reason equipped. You need to feel the brakes come on. This tells you the trailer brakes room connected and working. (The trailer brakes must be tested with the hand valve, however controlled in normal procedure with the foot pedal, which applies air come the service brakes at every wheels.)


Test your Knowledge

What is a converter dolly?Do converter dollies have spring brakes?What 3 methods can you usage to secure a 2nd trailer prior to coupling?How carry out you inspect to make sure trailer elevation is correct prior to coupling?What do you examine when making a visual examine of coupling?Why need to you traction a dolly out from under a trailer prior to you disconnect the from the trailer in front?What should you inspect for once inspecting the converter dolly? The pintle hookShould the shut-off valves ~ above the rear of the last trailer be open or closed? on the an initial trailer in a set of doubles? top top the middle trailer of a collection of triples?How have the right to you test the air flows to all trailers?

Study sections 7.1 through 7.4 if girlfriend can"t answer all of these questions.