What will happen if the lines are crossed when you hook up to an old trailer?

The driver crosses the air lines when hooking up to an old trailer. A If the trailer has no spring brakes, you can drive away, but you will not have trailer brakes. B The brake pedal will work the trailer spring brakes instead of the air brakes.

What will happen if the airlines are crossed when you hook up to an older trailer before 1975?

What will happen if the air lines are crossed when you hook up to an old trailer? If the trailer has no spring brakes, you could drive away but you would not have trailer brakes. The front trailer supports are up and the trailer is resting on the tractor.

What happens when you cross the air lines of an older trailer without spring brakes?

You cross the air lines when hooking up to an old trailer. What will happen? If the trailer has no spring brakes, you could drive away buy you wouldn’t have trailer brakes.

What happens when air lines are crossed?

If the air supply in the trailer air tank has leaked away, there will be no emergency brakes and the trailer wheels will turn freely. If you cross the air lines, you can drive away but you will not have trailer brakes.

When you get ready to back under the trailer line up?

4. When you get ready to back under the semi trailer you should line up: A About 12 degrees off the line of the trailer.

What is one thing you should do before backing under a trailer?

CDL

What should you hook up before backing under a trailer?

Before backing under the trailer you should: C= Supply air to the trailer system, then pull out the air knob. C= Supply air to the trailer system, then pull out the air knob. Before backing under the trailer you should: A= Pull ahead to test glad hands connections.

What is the 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 part of the kingpin should the locking jaws?

Check to make sure of the following: There is no space between the upper and lower fifth wheel, the fifth wheel jaws have closed around the shank of the kingpin, the locking lever is in the “lock” position, and the safety latch is in position over the locking lever.

What might happen if the trailer is too high when you try to couple?

What might happen if the trailer is too high when you try to couple? If the trailer is too low, the tractor may stike and damage the trailer nose; if the trailer is too high, it may not couple correctly. If there is space something is wrong and the trailer would come loose very easily.

When you turn suddenly while pulling doubles which trailer is most likely to turn over?

When you turn suddenly while pulling doubles, which trailer is most likely to turn over? Because of rearward amplification, the last trailer on a combination vehicle has the highest probability of rolling over. This is called the crack-the-whip effect.

What two things can a driver do to prevent rollovers?

The following two things will help you prevent rollover– keep the cargo as close to the ground as possible and drive slowly around turns. Keeping cargo low is even more important in combination vehicles than in straight trucks. Also, keep the load centered on your rig.

What happens if you hook up to an old trailer?

What will happen if the air lines are crossed when you hook up to an old trailer? a. The hand valve will apply the tractor brakes instead of the trailer brakes. b. The brake pedal will work the trailer spring brakes instead of the air brakes. c.

What should you do when backing up under a trailer?

When backing up under a trailer, you should line up Directly in front of the trailer You’re hooking up a tractor and semi-trailer, and you’ve connected both air lines. Before backing under the trailer you should Supply air to the trailer system, then pull out the air supply knob to lock the trailer brakes

When to lower landing gear on loaded trailer?

19) When you are uncoupling a loaded trailer, you should lower the landing gear until it: a) Makes firm contact with the ground, then turn the crank handle a few extra turns b) Makes firm contact with the ground and lifts the trailer off the fifth wheel c) Reaches the ground

What happens if your emergency air line breaks?

Your emergency air line breaks or gets pulled apart while you are driving. The loss of pressure will cause the: a. Emergency trailer brakes to come on. b. Tractor’s air to dump into the trailer tank through the service line. c. Air compressor to unload instead of pumping air.

What will happen if the air lines are crossed when you hook up to an old trailer? a. The hand valve will apply the tractor brakes instead of the trailer brakes. b. The brake pedal will work the trailer spring brakes instead of the air brakes. c.

Your emergency air line breaks or gets pulled apart while you are driving. The loss of pressure will cause the: a. Emergency trailer brakes to come on. b. Tractor’s air to dump into the trailer tank through the service line. c. Air compressor to unload instead of pumping air.

What happens when a combination vehicle breaks away?

You are driving a combination vehicle when the trailer breaks away , pulling apart both air lines. You would expect the trailer brakes to come on and: a. The tractor to lose all air pressure. b. Go off about every 2 seconds. c. The trailer supply valve to stay open. d. The tractor protection valve to close. d. The tractor protection valve to close.

When to back a tractor under a trailer?

You have pushed the trailer air supply valve. You should not back a tractor under a trailer until the whole air system is: At normal pressure. You are coupling a tractor to a semitrailer. You have connected the air lines. Before backing under the trailer you should: Supply air to the trailer system, then pull out the air supply knob.