Hydraulics Exam Bank Questions

Question 1

Which of the following best describes a piston type hydraulic actuator?
A) It is the simplest type of single acting cylinder.
B) Any oil trapped between the piston seal rings and the cylinder packing will flow into the piston tube though 6 holes at the lower end of the tube.
C) A guide ring supports the inner end of the piston tube but does not seal the piston in the cylinder barrel.
D) With each successive stage of the pump actuation force generation is reduced and speed increases.

Answer 1

B

Question 2

In variable displacement axial piston motors, stops prevent the swash plate from moving beyond a range of 6.5 to how much percent from perpendicular?
A) To 23 percent.
B) To 19 percent.
C) To 11 percent.
D) To 9 percent.

Answer 2

B

Question 3

Which of the following best describes a hydraulic Piston type motor?
A) A disc valve controls the flow of oil to and from the motor.
B) They rely on centrifugal force from the driveshaft.
C) A spool valve controls the flow of oil to and from the motor.
D) In general they are the most efficient type of hydraulic motor.

Answer 3

D

Question 4

Which of the following is true with respect to vane pump construction?
A) Vane pumps’ most common construction uses a one piece pump housing.
B) Vane pumps cannot be built to provide variable displacement.
C) Vane pumps are more complex and precisely constructed than an equivalent gear pump.
D) Vane pumps are inexpensive to purchase and repair compared to an equivalent gear pump.

Answer 4

C

Question 5

What hydraulic pump type can operate at the highest pressures?
A) Vane.
B) Balanced vane.
C) External drive.

Answer 5

B

Question 6

In a closed hydraulic system with a fixed displacement pump, the unloader valve acts like a relief valve when the cylinder is in operation because it dumps the oil flow of the pump to the reservoir if the cylinder encounters excessive load.
A) True
B) False

Answer 6

A

Question 7

What are detents?
A) A type of linear motion.
B) A time when valves are in the up position blocking oil.
C) They hold a directional control valve in position.
D) A time when valves are in the down position allowing oil to flow.

Answer 7

C

Question 8

With hydraulic actuators, the greater the internal capacity, what happens to the actuator speed for a given flow rate?
A) It is faster.
B) It is slower.

Answer 8

B

Question 9

Upon inspection you see that the cylinder barrel is heavily damaged. What should you do?
A) Weld over the dent.
B) Retube the barrel.
C) Ignore it if it is still working.
D) Put in an extra think piston seal.

Answer 9

B

Question 10

Where are anti cavitations check valves located?
A) Between the pump port and the directional control spool.
B) In directional control valves.
C) In directional control valve housings.
D) Between the work port and the return passage in the directional control valve.

Answer 10

D

Question 11

With a bent axis piston motor, at a given flow rate, the greater the angle the slower the motor will rotate. What will happen to the torque generated?
A) The torque generated will decrease.
B) The torque generated will increase.

Answer 11

B

Question 12

It has been determined that the hydraulic system has been contaminated. What should you do?
A) Flush the entire system.
B) Ensure that the oil is screened prior to reinstalling it.
C) Run the system at high speed to ensure adequate flow rate is occurring.
D) Bring the system to a high temperature to kill contaminates.

Answer 12

A

Question 13

Which of the following are characteristics of a basic sequence valve?
A) A check valve is required for rapid return of reversible actuators.
B) They are NO devices.
C) The outlet port is connected to the circuit to be operated first in the sequence.
D) No drain line is required.

Answer 13

A

Question 14

With hydraulic systems the velocity of the liquid passing through the small sections of the pipe is how much as compared to the velocity through the wider sections?
A) It is less than the velocity through the wider sections.
B) It is greater than the velocity through the wider sections.
C) It is the same as the velocity through the wider sections

Answer 14

B

Question 15

What is the most common type of output device found on electro hydraulic heavy equipment?
A) Proximity switches.
B) Lights.
C) Solenoids
D) Motors.

Answer 15

C

Question 16

What does a cylinder cycle time test tell you?
A) It tells you the speed the cylinder is moving at.
B) It lets you know speed the oil is being filtered at.
C) It lets you know the RPM of the machine.
D) It tells you the thickness of the oil.

Answer 16

A

Question 17

With an open centre hydraulic system, varying the speed of the engine can be used to control the speed of the actuator, which does not effect engine power production.
A) True
B) False

Answer 17

B

Question 18

Which of the following can cause a failure on a hydraulic cylinder?
A) A dented cylinder.
B) An external leak.
C) A bent cylinder rod.
D) All of the above.

Answer 18

D

Question 19

Which of the following best describes a rotary spool valve?
A) They can handle relatively high pressures.
B) It is the most commonly used type of directional control valve.
C) They have higher internal leakage than other designs.
D) It is the simplest type of directional control valve.

Answer 19

C

Question 20

When is it permissible to hone a cylinder barrel?
A) Whenever you want.
B) When the barrel has been heavily damaged.
C) When an object has pierced the cylinder wall.
D) When the cylinder barrel is lightly scored.

Answer 20

D

Question 21

Which of the following is a characteristic of a parallel hydraulic circuit?
A) Motors would receive full pump flow.
B) It is a circuit used on motor grader front wheel drive applications.
C) The pressure acting on each motor will vary.
D) The stalling of a motor would affect other motors.

Answer 21

B

Question 22

What is a hydraulic circuit?
A) A group of interconnected hydraulic components.
B) All of the interconnected hydraulic components mounted on a vehicle.
C) One that allows pump oil to be recycled.
D) One that uses a constant horsepower prime mover.

Answer 22

A

Question 23

Which high viscosity oil has a thicker oil film?
A) The thinner high viscosity oils will have a thicker oil film.
B) The thicker high viscosity oils will have a thicker oil film.

Answer 23

B

Question 24

What type of equipment would likely use a constant horsepower open centre hydraulic system?
A) Mining truck.
B) Wheel loader.
C) Snow Plow.
D) Excavator.

Answer 24

D

Question 25

25. What is a Closed Centre Hydraulic System often called?
    A) Constant pressure.
    B) Constant flow.
    C) Demand torque.
    D) Demand flow

Answer 25

D

Question 26

What is the difference between cracking pressure and full flow pressure called?
A) Modulated pressure.
B) The constant.
C) Pressure override.
D) Pressure release.

Answer 26

C

Question 27

What is the path of oil flow in an open circuit HST system?
A) The path is continuous.
B) The path is not continuous

Answer 27

B

Question 28

Hydraulic gear motors are excellent torque generators.
A) True
B) False

Answer 28

B

Question 29

The spring constant of a valve spring is one of the most significant factors influencing the amount of override.
A) True
B) False

Answer 29

A

Question 30

Which of the following best describes a hydraulic vane motor?
A) A disc valve controls the flow of oil to and from the motor.
B) They rely on centrifugal force from the driveshaft.
C) They use spring force to ensure vane to cam ring contact at start up.
D) In general they are the most efficient type of hydraulic motor.

Answer 30

C

Question 31

Oils that have the same viscosity at mid range temperatures may perform differently in cold conditions.
A) True
B) False

Answer 31

A

Question 32

What is degradation failure?
A) A type of transient failure.
B) Surface wear.
C) A type of cylinder wear.
D) Contamination that enters through a filter.

Answer 32

B

Question 33

Which of the following is true with respect to emulsions of oil and water?
A) They are designed to operate at low temperatures.
B) They can support the growth of bacteria.
C) They provide excellent filming characteristics.
D) They do not retain contaminants.

Answer 33

B

Question 34

What is the small piston called in a pressure compensated hydraulic pump?
A) Boss.
B) Bias.
C) Stroking.
D) Stacking.

Answer 34

B

Question 35

What would a burnt oil smell indicate in hydraulic systems?
A) A normal condition.
B) Oxidation is present.
C) Oil viscosity is too high.
D) Oil viscosity is too low.

Answer 35

B

Question 36

It has been found that the cylinder rod has a nick in it. What should be done?
A) Nothing needs to be done if it is still working.
B) The rod needs to be replaced.
C) Remove the chrome material from the rod and replate it.
D) Weld a spot over top of the nick.

Answer 36

C

Question 37

Which of the following best describes a cylinder cushion?
A) A device that restricts the return oil from the cylinder which backpressures the piston and resists piston movement.
B) They are often used on equipment that has limited reservoir volume.
C) They are installed to create faster, lowering cycle times.

Answer 37

A

Question 38

What is a typical concern when dealing with differential cylinders?
A) Slow retraction speed.
B) High forces during extension.
C) Cylinder drift while in the hold position.
D) Piston seal packing failure

Answer 38

C

Question 39

Which of the following is a sign of contaminants in a hydraulic pump?
A) Components may appear sandblasted.
B) A cracked pump housing.
C) Components show a pitted pattern.
D) A blue coloring ion components.

Answer 39

A

Question 40

A pressure gauge is installed with a shut-off value and a tee to the main line. When is the shut-off value opened?
A) It is opened all the time.
B) It is opened only when a pressure reading is taken.
C) It is opened only when you believe there is low pressure.
D) It is opened once the oil hits operating temperature

Answer 40

B