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Comb,Air Brake,& D/T
combination, Air Brakes, and Double/Triple
| Question | Answer |
|---|---|
| Where should the tractor be when you INSPECT the landing gear after uncoupling the trailer ? | with the tractor frame under the trailer |
| while driving behind another vehicle, under good conditions ,you should allow at least ONE SECOND between your vehicle and the vehicle ahead for each __ feet of your vehicle length | 10 feet |
| There are two things that a driver can do to PREVENT A ROLLOVER. They are: (1) keep the cargo as close to the ground as possible and (2) | Go slow around turn |
| The AIR BRAKE leakage rate for a combination vehicle (ENGINEOFF,BRAKE OFF) should not be more than __ psi per minute | 3 |
| If you cannot complete your TURN WITHOUT entering another traffic lane , you should | Turn wide as you complete the turn |
| The higher the CENTER OF GRAVITY of your | easier to turn over |
| If the service line COME APART while you are driving a combination vehicle , but the emergency line stays together , what will happen right away | nothing is likely to happen until you try to apply the brake |
| GLAD HAND are usually connecting which of these ? | service and emergency air lines from the vehicle to the trailer |
| A driver crosses the air line when hooking up to an OLD TRAILER. what will happen | if the trailer has no spring brakes , you could drive away but you would not have trailer brakes |
| The HAND VALVE should be used | To test the trailer brakes |
| when driving a set of doubles, it is necessary to close which SHUT OFF valve in the last trailer" | Back Valve |
| You are about to back your tractor under a semitrailer. The trailer is at the right height when the: | trailer will be LIFTED SLIGHTY when the tractor back under it. |
| Your EMERGENCY AIR LINE BREAKS or gets pulled apart while you are driving. The loss of pressure will cause the: | Emergency trailer brakes to come on. |
| If the SPRING BRAKES ARE NOT RELEASED when you push the trailer air supply valve, you should | check air line connection |
| Air Brake - Equipped trailers MADE BEFORE 1975 | ARE NOT REQUIRED to have spring brakes |
| There are two things that a driver can do to prevent a rollover: they ARE 1 GO SLOW AROUNF TURNS, AND 2 | Keep the cargo as close to the ground as possible |
| After connecting the air lines but BEFORE BACKING UNDER THE TRAILER, YOU SHOULD: | Supply air to the trailer systems, then pull out the air supply knob. |
| which part if the KINGPIN should the LOCKING JAW CLOSE around | The Shank |
| How much space should be allowed between the UPPER and LOWER FIFTH WHEEL after coupling? | NONE |
| you have pushed the trailers 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 the semitrailer; you have connected the airline. Before backing under the trailer, you should. | Supply air to the trailer system, then pull out the air supply knob |
| you are COUPLING A TRACTOR to a semitrailer and have backed up, but are not under it. what should you hook up before backing under | The emergency and service air line |
| Tractor with a __ trailer requires the SHORTEST AMOUNT of stopping distance | Fully Loaded |
| After you have coupled the trailer, you should raise the landing gear by using. | Low Gear |
| You should air to the trailer tanks by: | PUSHING IN the trailer air supply valve |
| There are two things that a driver can do to prevent a rollover. They are: (1)GO SLOW AROUND TURNS, and (2): | Keep the cargo as close to the ground as possible |
| why should you be sure that the fifth wheel plate is greased as required | to prevent steering problems |
| When connecting the glad hands press the two seals with the couplers together at what degree to each other ? | 90 DEGREE |
| Which of these statements is true? | Bobtail tractors can take longer to stop than a combination vehicle loaded to MAXIMUM GROSS WEIGHT. |
| why should you lock the tractor's glad hands to each other (or DUMMY COUPLERS) when you are not towing a trailer | it will keep dirt or water out of the line |
| When backing a tractor UNDER A TRAILER, you should | always use the LOWEST REVERSE GEAR |
| After the trailer has been coupled to the tractor, the tractor protection control control valve should be placed in what positions | Normal Position |
| The FIFTH WHEEL locking lever is not locked after the jaws close around the kingpin. This mean that | The coupling is not right and should be fixed before driving the coupled UNIT |
| Off-tracking or cheating causes which of theses to follow the wider oath while making a turn | Tractor with two 27-feet trailers |
| The IRON TRAILER support are up, and the trailer is resting on the tractor. make sure | There is enough clearance between the tractor FRAME AND THE LANDING GEAR |
| When you are uncoupling a loaded trailer, you should lower the landing gear until it | MAKE FIRM CONTACT WITH GROUND, turn crank in low gear a few extra turns |
| What will happen if the air lines are CROSSED when you hook up to an old trailer ? | If the trailer has NO SPRING BREAK, you could drive away but you would not have trailer brakes. |
| To stop a trailer skid, you should: | Release the brakes |
| The air lines on a combination vehicle are often colored to prevent them from mixing up. The emergency line is __ and the service line is __ | Red,Blue |
| Semi-Trailers made before 1975 that are equipped with air brakes | often do not have spring brakes |
| The AIR LEAKAGE RATE for a combination vehicle (engine off, brake on) should not be more than __ psi per minute | 4 |
| compared to a straight TRUCK OR BUS , there are ___ thing to inspect in combination vehicles | More |
| When checking the TRAILER EMERGENCY brakes, the tractor protection control valve should be placed in what positions | Emergency |
| In normal driving, some drivers use the hand valve before the brake pedal to A PREVENT A JACK-KNIFE which of the statements is true | it should not be done |
| while checking if the trailer is SECURELY COUPLED to the tractor, the lading gears should be. | Slightly Raised |
| AIR AND ELECTRICAL lines from the tractors to the trailer should be | SECURED but with enough loop to turn. |
| You have a MAJOR LEAK in the service line, and you put on brakes. services air will escape and cause the | Trailer Emergency brakes to come on |
| A tractor with a __ trailer requires the MOST AMMOUNT of stopping distance. | Empty |
| When you get ready to back under a semi trailer you should line up | Directly in front of the trailers |
| You should not back a tractor under a trailer until the air system is | At normal pressure |
| After you look the kingpin into the FIFTH wheel, you should check the connection by: | Pulling the tractor ahead gently with the trailers brakes locked |
| When should you use the hand valve park a COMBINATION vehicle ? | Never |
| You have coupled with semitrailer, where should you put the iron trailer support before driving away | Fully raised with crank handle secured in its bracket |
| The safety latch for wheel locking lever must be __ for a coupling to be complete | over the locking lever |
| After you supply air to the trailer, make sure the air lines are not crossed an the trailer brakes are working. This is done by | Applying and releasing the trailer brakes and listening for the SOUND OF THE BRAKE |
| Before you back UNDER A TRAILER, make sure that | the trailer brakes are LOCKED. |
| How should you test tractor - SEMITRAILER connection for security? | PULL GENTLY forward in low gear against the locked trailer brakes then looks at it carefully |
| The front trailer supports are up, and the trailer is resting on the tractor make sure | Both option are correct |
| To UNLOCK the fifth wheel, the locking lever should be placed in the__ position | OPEN |
| The tractor protection valve will close, and the trailer emergency brakes will come on when there is a MAJOR LEAK in the __ brake line | Emergency |
| When coupling, the PROPER of the fifth wheels is | TILTED DOWN toward the end of the trailer. |
| What gear should the tractor ENGINE be in after you UNCOUPLE the trailer and are INSPECTING the trailer supports | NEUTRAL |
| When uncoupling the trailer, after you shut off the trailer air supply and lock the trailer brakes, you should. | Back up gently to ease pressure on the fifth wheel |
| You are driving a combination vehicle when the trailers breaks away, pulling apart both air lines. You expect the trailers brakes to come on and: | The tractor protection VALVE TO CLOSE |
| The APPLICATION PRESSURE GAUGE shows how much air pressure you: | Are applying to the brakes. |
| The spring brakes used on the chambers in a straight truck will bring you to a STOP when air pressure DROPS BELOW __ psi | 20 |
| Some air brake systems have an alcohol evaporator. What may happen if you don't keep the proper level of alcohol ? | Ice may form in the air brake valves and CAUSE BRAKE FAILURE |
| Your truck or bus has a dual air brake systems. If a low pressure warning comes on for only one system, what should you do? | Bring your vehicle to a COMPLETE STOP right away and safely park. continue only after the system is fixed. |
| Why drain water from compressed air tanks ? | water can freeze in cold weather and CAUSE BRAKE FAILURE |
| The safely valve is SET AUTOMATICALLY when pressure is | 150 |
| Your truck has a dual air system, and one of the systems loses its pressure. What will happen ? | Either the FRONT OR BACK brake will not be fully operational |
| Parking or emergency brakes of trucks and buses can be LEGALLY help on by __ pressure | Spring |
| if your truck or bus has dual parking control valves you can use pressure from a separate tank to | Release the spring emergency/parking brakes to move a SHORT DISTANCE |
| If your truck has properly functioning dual air brake system and minimum-size air tank the air pressure should be from 85 to 100 psi within iw many seconds? | 45 |
| How should you check that your service brake are working properly? | Park on level ground, WAIT UNTIL NORMAL air pressure is reached, release the parking brake and move forward slowly at about 5 mph. Then apply the brake firmly |
| A straight truck of bus air brake system should NOT LEAK AT THE RATE OF more than __ psi per minute with the engine off and the brake released | 2 |
| During normal driving, SPRING BREAKES are USUALLY held back by | Air Pressure |
| The AIR COMPRESSOR STOPS pumping air at what psi? | 125 |
| Excessive use of the service brakes results in overheating , which can led to | EXPANSION of the brake drums |
| The most common type of foundation brake found on heavy vehicles is the | S-CAM DRUM |
| If you must make an emergency stop, you should brake so you | can keep your vehicle in a straight line |
| Your truck or bus has a dual air brake system. If a low air pressure warning comes on for only one system, what should you do ? | Stop right away and safely park. Continue only after the SYSTEM is FIXED |
| If your vehicle has an alcohol evaporator every day during cold weather you should | Check and fill the ALOCHOL LEVEL |
| The air loss rate for a straight truck or bus with the engine off and the brakes on should not be more than: | 3 PSI in one minute |
| The driver must be able too see a low air pressure warning which comes on before pressure in the service air TANK FALLS BELOW__ psi | 60 |
| The braking power of the spring brakes | Depends on the services brakes being in ADJUSTMENT |
| The air brake lag distance at 55 mph on dry pavement adds about __ feet | 32 |
| Total stopping distance for air brakes is longer than that for hydraulic brakes due to _ distance | BRAKE LAG |
| It is accepted that too much heat caused by using your brake too often can also cause | Brake to fade or fail |
| Repeatedly partially increasing and pressing the brake pedal may result in | a loss of brake air pressure |
| The brake systems that applies and releases the brakes when the driver uses the BRAKE PEDAL l is the _ brake system | Service |
| A SLACK ADJUSTER free play needs to be adjusted if it is more than about__ when you pull hard on it | 1 Inch |
| An air brakes systems is fully CHARGED at what psi? | 125 |
| The brake pedal in an air BRAKR SYSTEM | Controls the air pressure applied to the brakes |
| The S-cam | FORCES the brake shoes against in the inside of brake drum |
| under normal conditions, in order to engage the parking brakes, the driver should | Apply brakes by pulling the parking brake control KNOB out |
| All AIR BRAKES -EQUIPPED vehicles have | A supply pressure GAUGE |
| With air brake vehicles, the parking brake should be used | whenever you leave the vehicle UNATTENDED |
| If the air compressor should develop a leak, what keeps the air in the tanks? | The ONE-WAY check valve |
| Which of these is not a proper time to apply the parking brakes | If the brakes are VERY HOT (e.g. just after coming down a steep grade). |
| With air brake vehicles, the PARKING BRAKE should be used | Any time when vehicle is parked |
| why should you drain water from compressed air tanks | Water can freeze in COLD weather and cause brake failure |
| If the spring brakes are on, when should you PUSH the brake PEDAL? | Never |
| To check the free play of manual slack adjuster of s-cam brakes, you should park on | Level ground, CHOCK the wheels and release the parking brake |
| Excessive heat caused by using your brakes too often can also cause | Brake to FADE OR FAIL |
| If you must make an emergency stop, you should brake so you | Can steer and keep your vehicle in a STRAIGHT LINE |
| The use of brake on a long and steep downgrade under normal conditions is only a supplement to | The braking EFFECT of the engine |
| The most important thing to do when a low air pressure warning comes on is | STOP AND SAFELY park as soon as possible |
| The PARKING OR EMERGENCY brake on a heavy vehicle can only be held in position by something that cannot leak away, like | Spring Pressure |
| Air braking takes more time than hydraulic braking because | Air brake take more time to flow through the line than HYDRAULIC fluid |
| When brake are applied, the brake shoes will press against the | Brake drum or DISC |
| The safety valve DISCHARGE automatically at the pressure of | 150 psi |
| Stab Braking | Apply your brakes all the way. RELEASE the brakes when wheels lock up. As soon as the wheels start roiling, apply he breaks fully again |
| If air pressure is not built up within the correct amount of time then | Air pressure may drop to a LOW POINT while driving, requiring an emergency stop |
| The safety VALVE reduces pressure at __ psi | 150 |
| What can LEGALLY hold a parking or emergency brake in position for a truck, truck tractor or bus? | spring pressure |
| The supply PRESSURE GAUGE shows how air much pressure. | is in the air tanks |
| The braking power of the spring brakes | Depends on the brake being in Adjustment |
| It is not safe to drive a vehicle that has brake drums with CRACKS that are longer than __ of the width of the friction area | 1/2 |
| Your brakes are fading when | You have to push harder on a brake pedal to control your speed on a DOWNGRADE. |
| If you vehicle has an alcohol evaporator, it is there to: | Reduce the risk of icing in air brake valves in cold weather. |
| The air compressor GOVERNOR controls | When air is PUMPED into the air TANKS |
| Modern air brakes combine THREE different systems, They are the service, the parking, and the __ brakes | Emergency |
| If you do not have automatic tank drains, how often should you drain the oil and water from of compressed air storage tanks? | At the end of each day of driving |
| The proper use of the brakes when going down a long steep grade after selecting a proper gear is to brake until your speed is about __ below the posted speed and release your brake | 5 MPH |
| In ideal conditions, a truck or bus with air brakes going at 55 mph would require the stopping distance of how many feet ? | More than 300 feet |
| When is it ok to leave your truck UNATTEND WITHOUT applying the parking brakes and choking the wheel? | Never |
| The stop light switch | TURN ON the brake light when you put on the air brakes |
| The _ show how much pressure is in the air tanks | SUPPLY PRESSURE GAUGE |
| To test air service brake, you should | BRAKE FIRMLY while slowly moving forward |
| If you are driving down a steep downgrade and have reached your SAFE SPEED of 40 mph, you would apply the service brake until your speed dropped to _ mph | 35 |
| If your truck has a dual air brakes system, and one of the systems is low on pressure | Either the FRONT OR REAR brakes will not be fully functional |
| What happens when your brake drums get VERY HOT? | THEY EXPAND |
| What is "wig wag" | A mechanical arm that signals low air pressure |
| With the hand valve on, you should test the trailer brakes by opening the services line valve at the rear of the trailer. When you do this, you should hear | Air escape from the open valve |
| You are driving with double trailers and must use your brakes to avoid a crash. For emergency braking, you should: | Use controlled or stab braking |
| Which of these statements about emergency steering is true ? | If you have traffic both sides of your vehicle and something is blocking your lane, a move to the right is still the best choice. |
| The converter dolly air tank drain valve on coupled double/triple trailers should be: | closed |
| To check if the converter dolly is securely coupled to the rear trailer, you should | Pull gently against the pin of the second trailer |
| You are visually checking the coupling of a converter dolly to the rear trailer. How much space should be between the upper and lower fifth wheel? | None |
| You are doing a walk-around inspection of a double or triple trailer rig. You should be sure the converter dolly air tank drain valves are _ and the pintle hook is __ | closed , latched |
| During normal operation, the brakes of the double/triple trailer are controlled by: | Foot pedal |
| Which of these will result in the best control on curves ? | Slow to the safe speed before entering, then accelerate slight trough the curve. |
| The best way to stop any skid is to: | Restore traction to the tire |
| You are driving a set of doubles, and a set of trailer wheels goes into a skid. which of these is most likely to occur? | You will have a trailer jackknife |
| You are driving on a slippery road during the day. What does the driver's manual say about how much space you should keep ahead of your truck? | Allow much more space than is needed for ideal driving conditions. |
| which of these is Not a good thing to do when driving on slippery road ? | use the engine brake or speed retarder |
| When testing the coupling of the double trailer, the landing gears of the rear trailer should be | Slightly raised |
| You must drive through deep or flowing water; you should not: | Drive through quickly |
| When you turn with the tractor/triple trailer combination, the wheel that off-track (cheat) the most are | The wheels of the last trailer |
| How can you be sure you supplied air to a second trailer | Go the rear of the second trailer and open the emergency line shut-off |
| Before you can supply air to the air tank of a second trailer, you need to | open the shut-off valves at the rear of the first trailers and close the shut off valves at the rear of the second trailer |
| The trailer air supply control should pop out when the air pressure falls into the pressure range of | 20 to 45 psi |
| What is likely to happen if the pintle hooks is unlocked with the dolly still under the second trailer. | The dolly tow bar may fly up |
| You should check trailer height before connecting a converted dolly to a second or third trailer. The trailer height is right when | The trailers will be raised slightly when the converter dolly is backed under it. |
| The best way to keep brakes from getting too hot while going down long grades is to | Go slow and use only light, steady pressure on the brakes |
| You are driving a 100-foot truck with double trailers at 30 mph. The road is dry, and visibility is good. You should keep at least __ seconds of space ahead of you | 10 |
| Which of these statements about managing space to the sides is true ? | you should avoid traveling next to other when possible |
| "crack-the-whip' effect occurs when: | you make a QUICK lane change |
| When driving a truck with more than one trailer, which trailer should be first behind the truck ? | The heaviest |
| You are driving at night and you must dim your headlights for traffic. Good speed management says you should | slow down. |
| Empty trucks | May have poor traction due to bouncing and wheel lockup |
| Which of these statements about the handling of doubles and triples is true | A sudden movement with the steering wheel can result in a tipped over rear trailer |
| If you want to couple a second trailer to your combination vehicle, secure it by using | Both if available |
| You are driving a 100-foot truck with double trailers at 50 mph. The road is dry, and visibility is good. You should keep at least __ second of space ahead of you | 11 |
| which of these statements about quick steering movement and double/triples is true | Doubles/Triples turn over from quick steering moves more easily than many vehicle |
| Converter dollies | Often do NOT have spring brakes |
| You want to hook your combination to a second trailer that has no spring brakes. to do this without wheel chocks, you should | Supply air to the trailer air system with the tractor and then disconnect the emergency line |
| which of these statements about managing space to the sides is true ? | You should avoid traveling next to others when possible |
| Some large trucks have curved mirrors these mirrors | Make thing seem smaller and further away than they really are |
Created by:
0321steve