Hydraulic Maintenance Troubleshooting MCQ Quiz — Part 2 of 5

A. two meshing gears trapping fluid between gear teeth and the housing, carrying it from inlet to outlet ✓ Correct answer

B. a flexible diaphragm pulsing fluid

C. reciprocating pistons in a cylinder block

D. a set of vanes sliding in a rotor slot

A. simpler, more rugged construction but lower efficiency and higher noise at high pressure ✓ Correct answer

B. extremely high volumetric efficiency at very high pressures

C. zero internal leakage regardless of wear

D. variable displacement as a standard feature

A. a screw-type rotor

B. sliding vanes in a rotor that move in and out against a cam ring as the rotor turns ✓ Correct answer

C. a swash plate driving reciprocating pistons

D. meshing external gear teeth

A. elimination of the need for filtration

B. lower cost only

C. inability to handle any pressure above 50 bar

D. quieter operation and good efficiency, often with wear-compensating vane designs ✓ Correct answer

A. Adjusting the angle of a swash plate relative to the piston block ✓ Correct answer

B. Rewinding the pump housing

C. Changing vane spring tension only

D. Changing the number of gear teeth in mesh

A. elimination of the reservoir

B. a fixed, unchangeable flow output regardless of demand

C. operation without any pressure compensator option

D. flow output that can be adjusted to match system demand, improving energy efficiency ✓ Correct answer

A. the volume of fluid the pump theoretically moves per revolution or per cycle ✓ Correct answer

B. the noise level produced during operation

C. the maximum pressure a pump can generate

D. the electrical current drawn by the pump motor

A. Displacement divided by viscosity

B. Displacement multiplied by pump shaft speed (RPM) ✓ Correct answer

C. Displacement minus reservoir volume

D. Displacement divided by pressure

A. the pump's noise output

B. actual output flow compared to theoretical output flow, accounting for internal leakage ✓ Correct answer

C. electrical efficiency of the drive motor only

D. the ratio of pump weight to displacement

A. resistance to flow in the circuit, such as a load, restriction, or relief valve setting ✓ Correct answer

B. the reservoir fluid level

C. the pump motor's electrical rating

D. the fluid's viscosity index alone

A. as flexible diaphragms around the shaft

B. radially around a central cam or eccentric, moving perpendicular to the shaft axis ✓ Correct answer

C. parallel to the drive shaft in a rotating cylinder block

D. in a single row like an inline engine only

A. only a motor and a cylinder

B. a compressor and air receiver

C. a single valve with no pump or motor

D. electric motor, pump, reservoir, relief valve, filter, and pressure gauge ✓ Correct answer

A. At least 50 times the pump's rated flow per minute

B. Exactly the same volume as one minute of pump flow, no more

C. Reservoir size has no relation to pump flow rate

D. About 2 to 3 times the pump's rated flow per minute, to allow settling and cooling ✓ Correct answer

A. allow filtered air to enter and exit as fluid level changes with cylinder movement, while keeping contaminants out ✓ Correct answer

B. increase internal tank pressure permanently

C. seal the tank completely airtight at all times

D. replace the need for a return line filter

A. connect the reservoir directly to the accumulator

B. act as the primary pressure relief device

C. separate the pump suction side from the return side, promoting settling of contaminants and air release ✓ Correct answer

D. increase fluid temperature

A. operation purely by electrical solenoid signal with no spring

B. a spring directly opposing system pressure on a poppet or spool, opening once set pressure is exceeded ✓ Correct answer

C. no moving parts whatsoever

D. always being installed on the suction line

A. operation without any pilot stage

B. no ability to relieve high flow rates

C. more stable pressure control with less override, especially at higher flows ✓ Correct answer

D. worse pressure override characteristics at high flow

A. the valve's rated maximum temperature

B. the difference between cracking pressure and full-flow pressure as flow through the valve increases ✓ Correct answer

C. the number of times the valve can be adjusted

D. the valve's physical size

A. cool the hydraulic fluid

B. replace the need for a pump entirely in all systems

C. permanently remove fluid from the system

D. store hydraulic energy for later use, absorb shock, or maintain pressure during leakage ✓ Correct answer

A. a floating piston with dynamic seals

B. an elastomeric bladder pre-charged with nitrogen gas inside a steel shell ✓ Correct answer

C. a solid steel diaphragm welded shut

D. no separation at all, gas and oil mix directly

A. a free-floating piston with seals sliding inside a cylindrical body ✓ Correct answer

B. an open connection between gas and oil

C. a rubber bag only

D. a fixed, non-moving partition

A. nitrogen increases fluid viscosity

B. nitrogen is cheaper than any other gas available

C. nitrogen is inert and non-combustible, reducing fire risk when in contact with pressurized oil ✓ Correct answer

D. air cannot be compressed at all

A. assume it is safe since the pump is off

B. disconnect it while still fully charged to save time

C. puncture the bladder with a sharp tool immediately

D. properly discharge the hydraulic pressure and the gas pre-charge per manufacturer procedure ✓ Correct answer

A. improved volumetric efficiency

B. a smooth, silent operation with no vibration

C. increased fluid viscosity index

D. a loud, rattling or knocking noise, often described as marbles or gravel in the pump ✓ Correct answer

A. a clogged or undersized suction strainer restricting pump inlet flow ✓ Correct answer

B. using fluid with too low a viscosity

C. an oversized suction line

D. excessive reservoir fluid level

A. no operational effect

B. reduced heat generation

C. cavitation due to the pump's inability to fully fill its chambers at speed ✓ Correct answer

D. improved pump priming performance

A. the pump has too much electrical power

B. the pump is oversized for the application

C. the pump receives excess fluid beyond its capacity

D. the pump inlet does not receive sufficient fluid to fully fill its pumping chambers ✓ Correct answer

A. no change in pump performance

B. cavitation and pump starvation due to inadequate suction head ✓ Correct answer

C. increased fluid viscosity

D. improved pump priming

A. improved lubrication

B. aerated fluid, resulting in noisy, spongy operation and potential pump damage ✓ Correct answer

C. increased pump displacement automatically

D. a decrease in system temperature

A. improved pump seal life

B. no measurable effect on pump life

C. automatic self-correction over time

D. premature bearing and shaft seal wear, vibration, and noise ✓ Correct answer

A. running some pumps, especially unidirectional gear or vane pumps, in reverse can cause immediate internal damage or lack of priming ✓ Correct answer

B. reverse rotation always increases pump life

C. it only affects pump color coding

D. rotation direction never matters for pumps

A. the relief valve is removed from the circuit

B. the reservoir is completely full

C. system pressure reaches the compensator's set point, to limit further pressure rise and flow ✓ Correct answer

D. system pressure drops below a preset minimum

A. reduced energy waste and heat, since excess flow is not continuously dumped across a relief valve ✓ Correct answer

B. higher heat generation at idle or standby conditions

C. guaranteed constant flow regardless of load

D. elimination of all filtration requirements

A. the color of the hydraulic fluid

B. ambient room temperature only

C. the pump's own weight

D. feedback of actual load pressure demand from the downstream actuator or valve ✓ Correct answer

A. properly maintained fluid level

B. a correctly sized suction strainer

C. correctly torqued suction fittings

D. worn or damaged pump internal components such as bearings, gears, or vanes due to normal wear or contamination ✓ Correct answer

A. contaminants increase the pump's rated pressure

B. abrasive particles cause accelerated wear on close-tolerance mating surfaces inside the pump ✓ Correct answer

C. contamination lowers fluid temperature

D. contaminants improve lubrication of close-tolerance parts

A. a clean suction strainer

B. worn internal pump clearances causing excessive internal leakage and low volumetric efficiency ✓ Correct answer

C. an overfilled reservoir

D. a new, correctly sized pump

A. flow totalizer with no pressure function

B. thermometer exclusively

C. pressure gauge, often with an isolator or snubber to reduce needle flutter ✓ Correct answer

D. tachometer only

A. permanently disconnect the gauge from the system

B. replace the pressure relief valve

C. protect the gauge from pressure spikes and pulsation by restricting flow to the gauge ✓ Correct answer

D. increase the accuracy of low-pressure readings only

A. a restricted suction line or partially clogged strainer causing partial starvation ✓ Correct answer

B. excess fluid in the return line

C. an overcharged accumulator

D. an oversized reservoir

A. wasted energy and excess heat generation as flow is dumped across the relief valve ✓ Correct answer

B. reduced wear on the relief valve

C. improved system efficiency

D. reduced fluid temperature over time

A. replacing the pump seals

B. adjusting the relief valve setting

C. ensuring the pump housing and inlet passages are filled with fluid, not air, before startup ✓ Correct answer

D. increasing system pressure to maximum

A. it can never be used in hydraulic systems

B. it operates only pneumatically

C. it has no gears at all

D. one smaller internal gear rotates inside a larger internal gear, rather than two external gears meshing side by side ✓ Correct answer

A. the gear ratio of external teeth

B. the angle between the cylinder block axis and the drive shaft axis ✓ Correct answer

C. the number of vanes engaged

D. the reservoir fluid level

A. supply the main pressure flow to the actuator

B. route internal leakage fluid from the pump housing back to the reservoir, often through a separate filtered path ✓ Correct answer

C. act as the suction line

D. increase pump displacement

A. no effect on the pump at all

B. increased pump displacement

C. shaft seal failure due to pressure exceeding the seal's rated limit ✓ Correct answer

D. improved shaft seal life

A. use only in pneumatic systems

B. extremely pulsating, noisy flow output

C. very smooth, low-pulsation, quiet flow delivery ✓ Correct answer

D. inability to handle any viscosity range

A. excellent volumetric efficiency

B. no maintenance action is needed

C. reduced volumetric efficiency, likely from internal wear or damage ✓ Correct answer

D. the pump displacement has increased

A. excessive system pressure, pump binding, or misalignment causing the motor to draw excess current ✓ Correct answer

B. the fluid level is too high, causing motor issues

C. the motor is oversized for the pump

D. the pump is operating at unusually low load

A. the pump's serial number sticker only

B. only the pump's paint condition

C. coupling alignment, mounting bolt torque, fluid condition, and abnormal noise or vibration trends ✓ Correct answer

D. nothing, since pumps are maintenance-free

It is for ITI, diploma and B.Tech students, apprentices and working technicians who want to test fault-finding knowledge. The explanations are written to teach the reason, not just the answer.

Attempt the quiz first without looking. Then open the answer key, read the explanation for every question you missed, and retake the part after a day to see whether the explanation stuck.

No, but the parts build on one another: fundamentals first, then components, then circuits and real-world scenarios. Part 5 is the best test of whether you can apply the earlier parts to a live fault.