Question 1

Which of the following best describes what is meant by a perfect vacuum?

Accepted Answer

A)  any pressure below atmospheric 
B)  a volume in which all matter is evacuated 
C)  suction side of a hydraulic circuit 
D)  a psia gauge reading of less than 14.7 
A)  any pressure below atmospheric 
B)  a volume in which all matter is evacuated 
C)  suction side of a hydraulic circuit 
D)  a psia gauge reading of less than 14.7 B

Question 2

Technician A says that when coupling hydraulic fittings,pipe seal compound should usually be applied to female ends only.Technician A says that when final torquing hydraulic fittings,two wrenches should always be used.Who is correct?

Accepted Answer

A)  Technician A only 
B)  Technician B only 
C)  Both A and B 
D)  Neither A nor B 
A)  Technician A only 
B)  Technician B only 
C)  Both A and B 
D)  Neither A nor B B

Question 3

What is used to apply force to an accumulator in a hydraulic circuit?

Accepted Answer

A)  spring force 
B)  weight force 
C)  gas pressure 
D)  all of the above 
A)  spring force 
B)  weight force 
C)  gas pressure 
D)  all of the above D

Question 4

Technician A says that changing the swash angle in a swashplate pump varies the displacement of the pump.Technician B says that some swashplate pumps are fixed displacement.Who is correct?

Accepted Answer

A)  Technician A only 
B)  Technician B only 
C)  Both A and B 
D)  Neither A nor B 
A)  Technician A only 
B)  Technician B only 
C)  Both A and B 
D)  Neither A nor B

Question 5

What is the nominal diameter of hydraulic hose rated at #6 dash?

Accepted Answer

A)  1/4 inch 
B)  3/8 inch 
C)  1/2 inch 
D)  5/8 inch 
A)  1/4 inch 
B)  3/8 inch 
C)  1/2 inch 
D)  5/8 inch

Question 6

Where might you find a cam-actuated,radial piston pump on a highway truck?

Accepted Answer

A)  fuel transfer pump 
B)  common-rail,diesel fuel injection system 
C)  PTO wet line kit 
D)  cab-lift hydraulics 
A)  fuel transfer pump 
B)  common-rail,diesel fuel injection system 
C)  PTO wet line kit 
D)  cab-lift hydraulics

Question 7

What type of valve is used as the primary directional control valve in most hydraulic circuits?

Accepted Answer

A)  ball and poppet 
B)  gate valve 
C)  spool valve 
D)  pressure relief valve 
A)  ball and poppet 
B)  gate valve 
C)  spool valve 
D)  pressure relief valve

Question 8

What is an application of a counterbalance valve?

Accepted Answer

A)  maintaining back pressure 
B)  acts as a relief valve 
C)  pressure reduction 
D)  safety pop-off 
A)  maintaining back pressure 
B)  acts as a relief valve 
C)  pressure reduction 
D)  safety pop-off

Question 9

Which of the following types of hydraulic hose should be used to sustain the highest pressures and surge spikes?

Accepted Answer

A)  fabric braid 
B)  single wire braid 
C)  multiple wire braid 
D)  spiral wire braid 
A)  fabric braid 
B)  single wire braid 
C)  multiple wire braid 
D)  spiral wire braid

Question 10

Technician A says that a reading of one psi on a pressure gauge is equal to approximately 2-inches of Hg (mercury)measured on a manometer.Technician B says that one inch of Hg is equivalent to approximately 2-inches of H20 on a manometer.Who is correct?

Accepted Answer

A)  Technician A only 
B)  Technician B only 
C)  Both A and B 
D)  Neither A nor B 
A)  Technician A only 
B)  Technician B only 
C)  Both A and B 
D)  Neither A nor B

Question 11

On a hydraulic circuit with a reservoir vented to atmospheric pressure,which of the following best explains what moves the fluid from the reservoir to the pump inlet?

Accepted Answer

A)  static head pressure from the atmosphere 
B)  suction at the pump inlet 
C)  inertia of fluid established at pump outlet 
D)  vortex of fluid flow through pump 
A)  static head pressure from the atmosphere 
B)  suction at the pump inlet 
C)  inertia of fluid established at pump outlet 
D)  vortex of fluid flow through pump

Question 12

Technician A says that a vane pump is classified as non-positive.Technician B says that a gear pump uses a positive displacement pumping principle.Who is correct?

Accepted Answer

A)  Technician A only 
B)  Technician B only 
C)  Both A and B 
D)  Neither A nor B 
A)  Technician A only 
B)  Technician B only 
C)  Both A and B 
D)  Neither A nor B

Question 13

If you had a pressure gauge calibrated in psia that was subject only to atmospheric pressure,what would be displayed on its scale at sea level?

Accepted Answer

A)  zero 
B)  14.7 
C)  29.8 
D)  101.3 
A)  zero 
B)  14.7 
C)  29.8 
D)  101.3

Question 14

Technician A says that ISO 32 is the most commonly used viscosity grade for hydraulic fluids.Technician B says that ISO 32 is equivalent to SAE 20 grade.Who is correct?

Accepted Answer

A)  Technician A only 
B)  Technician B only 
C)  Both A and B 
D)  Neither A nor B 
A)  Technician A only 
B)  Technician B only 
C)  Both A and B 
D)  Neither A nor B

Question 15

Technician A says that all gases can be classified as fluids.Technician B says that all liquids can be classified as fluids.Who is correct?

Accepted Answer

A)  Technician A only 
B)  Technician B only 
C)  Both A and B 
D)  Neither A nor B 
A)  Technician A only 
B)  Technician B only 
C)  Both A and B 
D)  Neither A nor B

Question 16

Which of the following is the equation used to calculate work in hydraulic circuits?

Accepted Answer

A)  force multiplied by distance 
B)  force divided by distance 
C)  area multiplied by pressure 
D)  area divided by pressure 
A)  force multiplied by distance 
B)  force divided by distance 
C)  area multiplied by pressure 
D)  area divided by pressure

Question 17

If you had a tubular column of one square inch diameter that extended from sea level to 50 miles into the stratosphere,how much would the air in the tube weigh?

Accepted Answer

A)  101.3 kilograms 
B)  14.7 kilograms 
C)  101.3 pounds 
D)  14.7 pounds 
A)  101.3 kilograms 
B)  14.7 kilograms 
C)  101.3 pounds 
D)  14.7 pounds

Question 18

Technician A says that an example of force is any kind of pushing effort.Technician B says that an example of force is any kind of pulling effort.Who is correct?

Accepted Answer

A)  Technician A only 
B)  Technician B only 
C)  Both A and B 
D)  Neither A nor B 
A)  Technician A only 
B)  Technician B only 
C)  Both A and B 
D)  Neither A nor B

Question 19

Which of the following will have most influence over the rpm of a hydraulic pump?

Accepted Answer

A)  output flow of oil 
B)  pressure of oil 
C)  input flow of oil 
D)  load applied to pump output 
A)  output flow of oil 
B)  pressure of oil 
C)  input flow of oil 
D)  load applied to pump output

Question 20

Which of the following would represent atmospheric pressure at sea level?

Accepted Answer

A)  14.7 psi 
B)  29.8 inches Hg 
C)  101.3 kPa 
D)  all of the above 
A)  14.7 psi 
B)  29.8 inches Hg 
C)  101.3 kPa 
D)  all of the above

Exam 13: Hydraulics

Which of the following best describes what is meant by a perfect vacuum?

Technician A says that when coupling hydraulic fittings,pipe seal compound should usually be applied to female ends only.Technician A says that when final torquing hydraulic fittings,two wrenches should always be used.Who is correct?

What is used to apply force to an accumulator in a hydraulic circuit?

Technician A says that changing the swash angle in a swashplate pump varies the displacement of the pump.Technician B says that some swashplate pumps are fixed displacement.Who is correct?

What is the nominal diameter of hydraulic hose rated at #6 dash?

Where might you find a cam-actuated,radial piston pump on a highway truck?

What type of valve is used as the primary directional control valve in most hydraulic circuits?

What is an application of a counterbalance valve?

Which of the following types of hydraulic hose should be used to sustain the highest pressures and surge spikes?

Technician A says that a reading of one psi on a pressure gauge is equal to approximately 2-inches of Hg (mercury)measured on a manometer.Technician B says that one inch of Hg is equivalent to approximately 2-inches of H20 on a manometer.Who is correct?

On a hydraulic circuit with a reservoir vented to atmospheric pressure,which of the following best explains what moves the fluid from the reservoir to the pump inlet?

Technician A says that a vane pump is classified as non-positive.Technician B says that a gear pump uses a positive displacement pumping principle.Who is correct?

If you had a pressure gauge calibrated in psia that was subject only to atmospheric pressure,what would be displayed on its scale at sea level?

Technician A says that ISO 32 is the most commonly used viscosity grade for hydraulic fluids.Technician B says that ISO 32 is equivalent to SAE 20 grade.Who is correct?

Technician A says that all gases can be classified as fluids.Technician B says that all liquids can be classified as fluids.Who is correct?

Which of the following is the equation used to calculate work in hydraulic circuits?

If you had a tubular column of one square inch diameter that extended from sea level to 50 miles into the stratosphere,how much would the air in the tube weigh?

Technician A says that an example of force is any kind of pushing effort.Technician B says that an example of force is any kind of pulling effort.Who is correct?

Which of the following will have most influence over the rpm of a hydraulic pump?

Which of the following would represent atmospheric pressure at sea level?

Introduction to Servicing Heavy-Duty Trucks

Shop Safety and Operations

Tools and Fasteners

Preventive Maintenance Program

Fundamentals of Electricity

Fundamentals of Electronics and Computers

Batteries

Charging Systems

Cranking Systems

Chassis Electrical Circuits

Diagnosis and Repair of Electronic Circuits

Multiplexing

Clutches

Standard Transmissions

Standard Transmission Servicing

Torque Converters

Automatic Transmissions

Automatic Transmission Maintenance

Electronically Automated Standard Transmissions

Electronically Controlled Automatic Transmissions Ecats

Driveshaft Assemblies

Heavy-Duty Truck Axles

Heavy-Duty Truck Axle Service and Repair

Steering and Alignment

Suspension Systems

Wheels and Tires

Truck Brake Systems

Hydraulic Brakes and Air-Over-Hydraulic Brake Systems

Abs and Ebs

Air Brake Servicing

Vehicle Chassis Frame

Heavy-Duty Truck Trailers

Fifth Wheels and Coupling Systems

Heavy-Duty Heating, ventilation, and Air Conditioning Systems

Filters

Technician A says that a reading of one psi on a pressure gauge is equal to approximately 2-inches of Hg (mercury)measured on a manometer.Technician B says that one inch of Hg is equivalent to approximately 2-inches of H₂0 on a manometer.Who is correct?