1. (401) Most air compressors are lubricated by using oil a. splash from the pistons. b. from the vehicle engine. c. splash from the rocker arms. d. from the vehicle transmission
b. from the vehicle engine.
2. (401) Which air compressor component, when lifted, moves the inlet valve off its seat to prevent the compressor from building up more air pressure? a. Piston.b. Camshaft. c. Unloader piston. d. Discharge valve.
c. Unloader piston.
3. (401) Which air system reservoir is connected to the output line of the air compressor? a. Supply. b. Dry tank. c. Secondary. d. Quick buildup.
a. Supply.
4. (401) Which air brake system component protects against excessive air pressure buildup in the event of governor failure? a. Check valve in the secondary line. b. Safety valve in the secondary tank. c. Check valve in the primary line. d. Safety valve in the supply tank.
d. Safety valve in the supply tank.
5. (401) The air system's automatic moisture ejector valve is manually drained by a. turning the handle clockwise. b. turning the handle counterclockwise. c. pulling the diaphragm spring outward. d. pushing the wire in the exhaust port upward.
d. pushing the wire in the exhaust port upward.
6. (401) In an air brake system, alcohol vapors from the alcohol bottle enter the system at the a. compressor's air exhaust. b. compressor's air intake. c. supply reservoir. d. governor port.
b. compressor's air intake.
7. (401) On an air gauge with both primary and secondary indicator needles, the primary system indicator needle is a. yellow. b. black. c. green. d. red.
c. green.
8. (401) The main difference between a floor-mounted foot valve and a suspended-type foot valve is the a. way they are mounted. b. primary air delivery routing. c. secondary air delivery routing. d. suspended-type control valve is operated by hand.
a. way they are mounted
9. (401) What air brake component is connected to the relay valve's supply port by an air line? a. Reservoir. b. Safety valve. c. Brake chamber. d. Foot-control valve.
a. Reservoir.
10. (401) The function of the quick-release valve on the air brake system is to a. speed up the exhaust of air from a particular component. b. speed up the application of air to a particular component. c. protect the secondary system in case of an air loss in the primary system. d. protect the primary system in case of an air loss in the secondary system.
a. speed up the exhaust of air from a particular component.
11. (401) In order to release the parking brakes, the parking brake-control valve is actuated by a. pushing up the lever to supply air to the parking brake chambers. b. pushing in the button to supply air to the parking brake chambers. c. pulling down the lever to remove air from the parking brake chambers. d. pulling outward the button to remove air from the parking brake chambers.
b. pushing in the button to supply air to the parking brake chambers.
12. (401) What valve protects the truck/tractor air system if there is an air loss in the trailer air system? a. Check valve. b. Safety valve. c. Quick-release valve. d. Tractor protection valve
d. Tractor protection valve
13. (402) A typical brake chamber's body and cover are held together by a. a clamp. b. a clevis. c. nuts and bolts. d. studs and nuts.
a. a clamp.
14. (402) A type 30 chamber indicates the a. outside diameter of the brake chamber is 30 centimeters. b. outside diameter of the diaphragm is 30 centimeters. c. diaphragm has an area of 30 square inches. d. diaphragm has an area of 30 cubic inches.
c. diaphragm has an area of 30 square inches
15. (402) On a vehicle equipped with a parking brake chamber, the parking brake is a. spring-applied. b. cable-applied. c. lever-applied. d. air-applied.
a. spring-applied.
16. (402) Undterm-14er normal driving operation, how is the parking brake held in the released position? a. Cam and S-lever. b. Air pressure in the parking brake chamber. c. Spring pressure in the service brake chamber. d. Spring pressure in the parking brake chamber.
b. Air pressure in the parking brake chamber.
17. (402) To service the basic parking brake chamber, you must manually cage the power spring by a. installing a C-clamp around the body and cover. b. installing a guide pin through the pushrod. c. using a special release stud. d. using large vise grips
c. using a special release stud.
18. (402) On the automatic slack adjuster, what component pushes the actuator rod and piston during brake release? a. Clevis. b. Hex roller. c. Return spring. d. Torque spider.
a. Clevis.
19. (403) At approximately what pressure in pounds per square inch (psi) should the air system's low air pressure warning light/buzzer activate? a. 60 psi. b. 70 psi.c. 80 psi. d. 90 psi.
a. 60 psi.
20. (403) Valves and their components can be cleaned with a mild solvent, and corrosion on the valves components can be removed with a. crocus cloth. b. emery cloth. c. wire wheel. d. sand paper
b. emery cloth.
21. (403) Why should you replace both brake chambers on the same axle? a. Ensures even braking. b. Increases braking effort. c. Prevents incorrect slack adjustment. d. Provides the correct air pressure setting.
a. Ensures even braking.
22. (403) The correct way to check slack adjuster operation and adjustment is to inspect the a. length of the diaphragm when the brakes are applied. b. length of the push rod stroke when the brakes are applied. c. angle between the slack adjuster and the camshaft when the brakes are applied. d. angle between the slack adjuster and the camshaft when the brakes are not applied.
b. length of the push rod stroke when the brakes are applied.
23. (403) Why must you be careful when greasing the foundation brake camshaft housing? a. Grease can contaminate the brake chamber diaphragm. b. The housing requires special high-temperature grease. c. Too much grease can contaminate the brake linings. d. Too little grease will cause brake lining wear.
c. Too much grease can contaminate the brake linings.
24. (403) What antilock brake system (ABS) component regulates air to the service brake chambers to prevent wheel lockup during aggressive braking? a. Control module. b. Wheel speed sensor. c. Quick-service valve. d. Front and/or rear modulator.
a. Control module.
25. (403) Where is the front tone ring mounted on an antilock brake system (ABS)? a. Spindle. b. Wheel hub. c. Backing plate. d. Wheel cylinder
b. Wheel hub.
26. (403) What is a major disadvantage when it comes to replacing the rear axle wheel-speed sensor on an antilock brake system (ABS)? a. Control module re-calibration. b. Re-lining the rear brakes. c. Differential disassembly. d. Wheel hub disassembly.
c. Differential disassembly.
27. (403) Interpreting fault codes from an antilock brake system (ABS) is accomplished by using a hand-held scanner or by a. recording a series of warning lamp flashes. b. cycling the ignition switch ON and OFF several times. c. turning ignition switch ON and stepping on the accelerator pedal. d. driving the vehicle and stopping abruptly to activate the ABS diagnostics.
a. recording a series of warning lamp flashes.
28. (403) How many diagnostic light emitting diodes (LED) are located in the diagnostic window of a two-channel air brake antilock brake system (ABS) control module? a. 4. b. 9. c. 12. d. 15.
b. 9.
29. (403) On an antilock air brake system (ABS), the control module diagnostics are cleared by a. disconnecting the control module's connector. b. disconnecting the rear axle speed sensor connector. c. pushing the RESET button on the diagnostic window. d. passing a small magnet over the RESET point in the diagnostic window.
d. passing a small magnet over the RESET point in the diagnostic window.
30. (404) The pressurized air used by the central tire inflation system (CTIS) is stored in the a. quick buildup air tank. b. right-hand air tank. c. accessory air tank. d. static air tank.
c. accessory air tank.
31. (404) What allows for rapid deflation in the central tire inflation system (CTIS)? a. Pilot air distribution manifold 1. b. Pilot air distribution manifold 2. c. Orifice bypass valve. d. Orifice valve.
c. Orifice bypass valve.
32. (404) What component shuts down the central tire inflation system (CTIS) if air pressure drops below 80 psi? a. Pressure regulator. b. Air pressure reservoir. c. CTIS low-pressure switch. d. Low-pressure indicator switch.
c. CTIS low-pressure switch
33. (404) What terrain condition is not a setting on the central tire inflation system (CTIS) controller? a. Swamp. b. Emergency. c. Cross-country. d. Sand/mud/snow.
a. Swamp.
34. (404) What is the timed operation controlled by the central tire inflation system (CTIS) controller? a. Fault code diagnostics. b. Engine shutdown. c. Automatic inflate. d. Mass deflate.
d. Mass deflate.
35. (405) The failure of the central tire inflation system (CTIS) to function properly is caused by the following conditions except a. air system leaks. b. malfunctioning controller. c. defective valve or faulty solenoid. d. terrain switch set for wrong driving conditions.
d. terrain switch set for wrong driving conditions.
36. (405) Before disconnecting any central tire inflation system (CTIS) air line, what should you do first? a. Drain the air system.b. Remove the bypass valve. c. Cage the park brake chambers. d. Disable the governor assembly.
a. Drain the air system.
37. (406) What is meant by the flow rate in a hydraulic system? a. Quantity of fluid viscosity detected at a certain point. b. Volume quantity of the liquid as it passes a point. c. Average speed of the fluid past a pint. d. Pressure exerted under resistance.
b. Volume quantity of the liquid as it passes a point.
38. (406) The term fluid power refers to a. energy that is transmitted via a fluid under pressure. b. energy that is transmitted via a fluid's viscosity. c. speed generated by hydraulic fluid. d. fluid flow torque.
a. energy that is transmitted via a fluid under pressure.
39. (406) What is meant by a dual or tandem hydraulic pump? a. Two pumps connected together individually operating separate systems (two input shafts). b. Two pumps connected together individually operating separate systems (one input shaft). c. A single hydraulic pump that operates multiple hydraulic functions. d. A single hydraulic pump that operates one hydraulic function.
b. Two pumps connected together individually operating separate systems (one input shaft).
40. (406) What type of pump has the inlet side sealed from the outlet side and delivers fluid anytime? a. Nonpositive displacement. b. Proactive displacement. c. Negative displacement. d. Positive displacement.
d. Positive displacement.
41. (406) A hydraulic motor is a pump that a. pulls fluid only. b. pushes fluid only. c. is being pulled instead of doing the pulling. d. is being pushed instead of doing the pushing.
d. is being pushed instead of doing the pushing.
42. (406) What is the purpose of an accumulator? a. Store hydraulic fluid for the pump to use. b. Store hydraulic fluid for a hydraulic motor to use. c. Store energy and keep system pressure relatively constant. d. Increase and maintain system pressure at the maximum pounds per square inch (psi).
c. Store energy and keep system pressure relatively constant.
43. (406) If you say a valve assembly is "zero overlap," then you mean a. the distance that the valve piston travels. b. there is no dead zone between active control ranges. c. the amount of play (excess space) inside the valve cavity. d. there is no change in fluid direction when the valve is moved.
b. there is no dead zone between active control ranges.
44. (407) Which device is used for removing larger contaminants from a fluid? a. Magnetic plug. b. Skimmer. c. Strainer. d. Filter.
c. Strainer.
45. (407) A filter that contains closely woven metal screens or discs is classified as a. free flowing. b. mechanical. c. osmotic. d. porous.
b. mechanical.
46. (407) In order to remove metal particles from hydraulic fluid, magnetic plugs are installed in the hydraulic oil a. strainer. b. cylinder. c. reservoir. d. return line.
c. reservoir.
47. (407) When the available fluid does not fill the existing space, it causes a. cavitation. b. capillary vibration.c. low-pressure shutoff. d. excessive system pressure.
a. cavitation.
48. (407) To resist pitting and scoring, hydraulic cylinder shafts usually coated with hard a. copper plate. b. chrome plate. c. nickel cadmium. d. aluminum oxide.
b. chrome plate.
49. (407) What is the first step for checking a pressure relief valve? a. Turn adjusting screw all the way out to relieve pressure. b. Turn adjusting screw all the way in to relieve pressure. c. Check the valve's internal ports for dirt and debris. d. Check system pressure to ensure proper relief.
d. Check system pressure to ensure proper relief.
50. (407) A hydraulic valve bank is designed to support a. storing of hydraulic fluid for pump operation. b. cleaning and recirculating of hydraulic fluid. c. multiple valve functions. d. a single valve function.
c. multiple valve functions.
51. (407) The following conditions are signs that a hydraulic hose needs to be replaced except a. leaking. b. cracking.c. flatness and blistering. d. low reservoir fluid level.
d. low reservoir fluid level.
52. (407) If a schematic is unavailable, you can isolate hydraulic system problems by a. replacing each component until the problem is found. b. running the system at high-speed and listening. c. overfilling the reservoir and looking for leaks. d. tracing the hydraulic circuit.
d. tracing the hydraulic circuit.
53. (408) When conducting a visual inspection on the hydraulic system, what component should you ensure is in the open position? a. Hydraulic return valve. b. Reservoir drain valve. c. Filter bypass valve. d. Tank shut-off valve.
d. Tank shut-off valve.
54. (408) Your final step after completing an inspection of all lines and hoses is to look for a. visible air leaks. b. improper tire wear. c. visible hydraulic leaks. d. rust on the cylinder rams.
c. visible hydraulic leaks
55. (408) An audible squeal noise occurring while operating the hydraulic system is a symptom of a. loose belts. b. missing belts. c. belts too tight. d. properly adjusted belts.
a. loose belts.
56. (408) What do you compare readings to after taking pressure readings of the hydraulic pump? a. Same pressure readings from another same style of vehicle. b. Service manual or technical order specifications.c. Pressure readings from another hydraulic system. d. Pressure readings taken by another technician.
b. Service manual or technical order specifications.
57. (408) What is the second step in removing the hydraulic pump? a. Loosen the pump inlet hose/line. b. Disconnect the pump outlet line. c. Shut off the in-line ball valve. d. Cap all hydraulic lines.
c. Shut off the in-line ball valve.
58. (408) Once you have installed the hydraulic cylinder and connected all lines, what is your next step? a. Bleed the air out of the cylinder. b. Test under max rated load. c. Ensure there are no leaks. d. Add hydraulic fluid.
a. Bleed the air out of the cylinder.
59. (408) How many volts should be measured at the solenoid? a. 6 volts. b. 10 volts. c. 12 volts. d. 24 volts.
c. 12 volts.
60. (408) When you test a valve assembly by applying 12 volts to the solenoid, what are you looking for? a. Heating of the solenoid. b. Valve movement and operation. c. Solenoid movement or operation. d. Jumping of the valve and solenoid.
b. Valve movement and operation.
61. (409) You can lower the boiling (vaporizing) point of a closed container of liquid by a. going to the lowest possible sea level and heating the container. b. placing a partial pressure over the container. c. decreasing the pressure over the container. d. placing a vacuum over the container.
c. decreasing the pressure over the container.
62. (409) Refrigerant-12 (R-12) was phased out because it was a. too expensive to produce. b. dangerous to technicians. c. less efficient than R-134a. d. dangerous to the environment.
d. dangerous to the environment.
63. (409) The air conditioning system cools the passenger compartment when the blower a. forces air through the condenser. b. forces air through the evaporator. c. compresses and circulates the refrigerant. d. disperses refrigerant into the passenger compartment.
b. forces air through the evaporator.
64. (409) Which of the following is not a function of an air conditioning system? a. Cools air. b. Cleans air. c. Circulates air. d. Humidifies air.
d. Humidifies air.
65. (409) What state is the refrigerant in when it leaves the evaporator? a. High-pressure gas/vapor. b. Low-pressure gas/vapor. c. High-pressure liquid. d. Low-pressure liquid.
b. Low-pressure gas/vapor.
66. (409) What kind of force locks the air conditioning compressor's clutch plate and pulley together when the compressor clutch is energized? a. Centrifugal. b. Magnetic. c. Spring. d. Static.
b. Magnetic.
67. (409) Air conditioning refrigerant hoses are designed to withstand compressor pressures, measured in pounds per square inch (psi), as high as a. 50 psi. b. 125 psi. c. 250 psi. d. 1000 psi.
c. 250 psi.
68. (409) Where is the condenser located and what is its function? a. Inside the heater case; transfer heat from the refrigerant to outside air. b. In front of the radiator; transfer heat from the refrigerant to outside air. c. Under the dash; transfer heat from the passenger compartment to the refrigerant. d. In front of the radiator; transfer heat from the passenger compartment to the refrigerant
b. In front of the radiator; transfer heat from the refrigerant to outside air.
69. (409) If a vehicle has a sight glass, where is it normally located if it is not on the receiver-drier? a. On the compressor. b. In a refrigerant line. c. On the accumulator. d. Behind the glove box.
b. In a refrigerant line.
70. (409) What component of an air conditioning system prevents liquid refrigerant from entering the compressor? a. Reed valve. b. Orifice tube. c. Accumulator. d. Receiver-drier.
c. Accumulator.
71. (409) The compressor cycling switch cycles the compressor to maintain the correct temperature of the a. condenser fins. b. receiver-drier. c. evaporator. d. condenser.
c. evaporator.
72. (409) The expansion valve controls a. when the compressor turns on. b. when the compressor turns off. c. how much refrigerant enters the evaporator. d. how much pressure is exerted on the refrigerant.
c. how much refrigerant enters the evaporator.
73. (409) A passenger compartment electrically-charged air filter can trap particles as small as a. 2 microns. b. 5 microns. c. 15 microns. d. 50 microns.
b. 5 microns.
74. (410) On a vehicle equipped with a sight glass, what condition is indicated if the air conditioning (A/C) system does not cool and bubbles appear in the sight glass? a. A desiccant bag is broken. b. Refrigerant is low and air is in the system. c. The system is overcharged with refrigerant. d. The system is completely out of refrigerant.
b. Refrigerant is low and air is in the system.
75. (410) If refrigerant contacts your skin, it can cause severe a. frostbite. b. cracking. c. irritation. d. chemical burns.
a. frostbite.
76. (410) What external factor can affect readings when testing an air conditioning (A/C) system using a pressure or manifold gauge assembly? a. Outside temperature. b. Engine temperature. c. Humidity. d. Altitude.
a. Outside temperature.
77. (410) When connecting R134a quick-disconnect fittings, in what position should the thumb screws be? a. Low side turned out; high side turned in. b. Low side turned in; high side turned out. c. Both turned all the way out. d. Both turned all the way in.
c. Both turned all the way out.
78. (410) When conducting an air conditioning (A/C) performance test, if the system is functioning correctly, the dash vent temperature reading in degrees Fahrenheit (° F) should be approximatelya. 30-45 ° F. b. 38-60 ° F. c. 42-57 ° Fd. 45-65 ° F.
b. 38-60 ° F.
79. (410) What type of detector causes air conditioning (A/C) leaks to show up as a bright color spot? a. Internally charged. b. Electronic. c. Bubble. d. Torch
a. Internally charged.
80. (410) One of the most common sources of air conditioning (A/C) system leaks are a. damaged O-rings. b. cracked condensers. c. aging refrigerant lines. d. loose refrigerant line fittings.
d. loose refrigerant line fittings.
81. (410) Which of the following does not indicate air conditioning (A/C) compressor problems? a. High inlet pressure. b. A loud rattling noise. c. Low discharge pressure. d. A click when the compressor engages.
d. A click when the compressor engages.
82. (410) When evacuating an air conditioning (A/C) system, approximately how many inches of mercury (in. Hg) at sea level should you pressure gauge display while operating the vacuum pump? a. 5-10. b. 13-14. c. 26-28. d. 34-40.
c. 26-28.
83. (410) When checking coolant flow through the heater core, how can you tell if the system has a blockage or is clogged? a. Coolant is dripping out of the condensation drain tube. b. Both heater hoses are about the same temperature. c. The blower motor will not operate at any speed. d. One heater hose is hot and the other is cool.
d. One heater hose is hot and the other is cool.
84. (411) Which of the following tests is used to analyze how well a vehicle's body-frame structure and restraint systems will protect the occupants? a. Crush zone test. b. Dummy test. c. Crash test. d. Beam test.
c. Crash test.
85. (411) What type of restraint is an air bag? a. Active. b. Passive. c. Collapsible. d. Retractable.
b. Passive.
86. (411) Which response best describes the amount of time it takes for an air bag to inflate after an impact sensor has detected a collision? a. 1 to 2 seconds. b. 10 milliseconds. c. One-half second. d. One-twentieth of a second.
d. One-twentieth of a second.
87. (411) The largest air bag in a dual air bag system is the a. passenger-side air bag. b. driver's-side air bag. c. side-impact air bag. d. rear seat air bag.
a. passenger-side air bag.
88. (411) Each of the following types of air bags are found in vehicles except a. side-impact air bags. b. side curtain air bags. c. inflatable seat belts. d. overhead air bags
d. overhead air bags
89. (411) How fast in miles per hour (mph) can an air bag travel during deployment? a. 100 mph. b. 150 mph. c. 200 mph. d. 300 mph.
c. 200 mph.
90. (411) Front impact air bag sensors are often located in the a. trunk. b. doors. c. passenger area. d. engine compartment.
d. engine compartment.
91. (411) Which of the following is not an air bag sensor? a. Proximity sensor. b. Coil spring sensor. c. Accelerometer sensor. d. Arming or safing sensor.
a. Proximity sensor.
92. (412) During a seat belt inspection, you should check the webbing for all of the following except a. cuts. b. twisting.c. color fading. d. excessive moisture
d. excessive moisture
93. (412) When servicing a seat belt, what should you do if you find a bent buckle? a. Replace the seat belt assembly. b. Straighten the buckle using heat. c. Measure the angle of the bend and compare it to specifications. d. Straighten the buckle with vice grips and tighten the anchor bolts with a torque wrench
a. Replace the seat belt assembly.
94. (412) What is the recommended procedure for disarming the air bag system? a. Short the air bag sensor to ground to release the stored energy from the capacitor. b. Specified by the manufacturer; refer to the service manual. c. Pull the ignition fuse from the fuse block. d. Disconnect the air bag fusible link.
b. Specified by the manufacturer; refer to the service manual.
95. (412) What is the minimum amount of time you should allow an air bag to cool before handling it after deployment? a. 5 minutes. b. 10 minutes. c. 15 minutes. d. 30 minutes.
d. 30 minutes.
96. (412) After air bag deployment, which of the following should not be done? a. Place tape over air bag vent holes. b. Vacuum the passenger compartment. c. Wear a respirator, goggles, and rubber gloves. d. Force excess powder out of the air bag using hand pressure.
d. Force excess powder out of the air bag using hand pressure.
97. (412) When carrying a live (undeployed) air bag module, how should you aim the trim cover? a. Away from your body. b. Toward your body. c. Toward the floor. d. Upward.
a. Away from your body.
98. (412) After deployment from a collision, what air bag sensors should be replaced? a. All sensors. b. Crash sensors only. c. None; they need to be reset. d. Only those triggered in the collision
a. All sensors.