If your test of the tractor protection valve is successful,the tractor protection valve control trailer air supply control

SC CDL Permit Practice Flashcards If your test of the tractor protection valve is successful,the tractor protection valve control (trailer air supply control) will pop out or go from "normal" to "emergency" After you lock the kingpin into the fifth wheel, how should you check the connection?Pull the tractor ahead gently with the trailer brakes locked.If the trailer has antilock brakes (ABS) but the tractor doesn't, the trailer is less likely to swing out.What is the safest way to turn right from a two-way road?Turn wide as you complete the turn To drive a triple combination vehicle, you must havea Class A CDL with a Doubles/Triples (T) endorsement When you inspect the landing gear after uncoupling the trailer, where should the tractor be?With the tractor frame under the trailer On a trailer, where is the yellow antilock brake (ABS) malfunction lamp located?On the left front or left rear corner If your vehicle gets stuck on a railroad track, you shouldget away from your vehicle and call 911 or the posted emergency number The tractor protection valve is designed to close automatically if the air pressure falls into the pressure range specified by the manufacturer, typically 20 to 45 psi Before you start to uncouple, you mustmake sure the ground is solid and can support the weight of the trailer As part of your vehicle inspection test, if your vehicle is equipped with air brakes and has a trailer, you will inspect the air connections between the truck or tractor and the trailer. Make sure that the ________ are locked in place and free of damage or air leaks.glad hands To prevent a rollover, cargo should bespread evenly across the rig and as low as possible Which statement best illustrates the "crack-the-whip" effect?If you make a quick lane change or sudden movement of your steering wheel, your trailers will tend to swing out. The rearmost trailer will swing out the most and will be most likely to roll over.Combination vehicles take longer to stop when they are empty than when they are fully loaded, because there is less traction During uncoupling, you should disconnect the electrical cable and hang it with the plug down.When you're pulling doubles or triples, the shut-off valves should always be open except for those on the last trailer After coupling, make sure that the air lines are not crossed.How should you do this?Adjust the air supply knob to send air to the trailer brakes.Turn off the engine once the air pressure normalizes. Then listen to the sound of escaping air as the brakes are released.After you connect the air lines but before you back under the trailer, you should supply air to the trailer system and then pull out the air supply knob.

Even before antilock braking systems (ABS) were required, some vehicles already had them. How can you check if your vehicle has ABS?Look under the vehicle for the electronic control unit (ECU) and wheel speed sensor wires coming from the back of the brakes You can confirm that air is going to all brakes in your trailers by opening the emergency line shut-off valve and then the service line valve at the rear of the last trailer and listening for air escaping each time.To test the tractor protection valve, charge the trailer air brake system, turn off the engine, and step on and off the brake pedal several times On a double or triple vehicle, which wheels offtrack the most?The rear wheels of the last trailer To uncouple a loaded trailer, after the landing gear has made firm contact with the ground, you should turn the crank a few more times to lift some weight off the tractor An antilock braking system (ABS) is useful whether it is on the tractors or the trailers Low-slung vehicles can be risky at railroad crossings because they are more likely to get stuck on raised railroad crossings.