190301e Flashcards

1
Q

A quick method to check for internal leakage in a double-acting cylinder is to stall
the cylinder, remove the return line and measure the amount of oil flowing past the
piston seals.T/F

A

true

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2
Q

If cylinder hydraulic lines are reversed from their original position when the cylinder
is installed:

A

the cylinder will function opposite to normal operation.

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3
Q

A quick and acceptable method of removing the piston and rod assembly from the
cylinder barrel is to apply compressed air to the base end of the cylinder.T/F

A

false;

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4
Q

A rough determination of cylinder rod straightness can be made by using a straight
edge. A more accurate determination is made by:

A

rotating the cylinder rod while it is supported in V-blocks and reading the amount of
deflection on a dial indicator.

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5
Q

It is possible to remove the damaged chrome surface from a cylinder rod and replace
it with new material using an electroplating process.T/F

A

true

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6
Q

In order to completely analyze a hydraulic motor failure, you must consider several
contributing causes. List four (4).

A

a) the condition of each motor part
b) type and condition of hydraulic oil and filters
c) operating conditions and symptoms before failure
d) conditions of other hydraulic system components

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7
Q

Which of the following is not evidence that a hydraulic motor has failed due to lack
of lubrication?

A

pitted erosion on motor components

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8
Q
List four (4) start-up procedures that should be observed after a hydraulic motor is
installed
A

a) Back off system pressure controls.
b) Operate the motor at no load and check for leaks or unusual noises.
c) Apply a load to the motor and warm up the hydraulic oil. Adjust system pressure
controls.
d) Perform operational tests to confirm that the machine is performing satisfactorily.

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9
Q

What are the ways that a lack of lubrication may occur in a motor?

A

Improper hydraulic oil
Low reservoir oil
Severe aeration

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10
Q

What is the lack of lubrication evidence?

A

Heavy wear on moving surfaces.
Blue coloring, indicating an overheat condition.
Smearing and metal transfer.
Motor seizure in severe cases.

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11
Q

Cleanliness is critical for hydraulic pump motors. T/F

A

True. Because of low clearances and low tolerances for contamination.

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12
Q

You should check for motor driveshaft wear and misalignment. T/F

A

True

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13
Q

Certain shafts need to be lubricated before installation. T/F

A

True.

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14
Q

What are 4 main start up procedures for when you have installed a motor?

A

Back off the system pressures prior to start up. This prevents overloading in case of a misadjusted relief valve.
Operate at no load checking for leaks and unusual noises.
Apply a load to the motor and warm the oil to operating temperatures. Then set relief.
Perform operational tests and check cycle times.

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15
Q

Hydraulic motors can be large and heavy and are sometimes mounted in awkward locations, what are some precautions we should take? (2)

A

Use hoists and lifting equipment wherever possible and use proper manual lifting techniques when required.

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16
Q

When a motor is removed,it’s acceptable to leave the lines hanging down so dirt doesn’t get in the system. T/F

A

False; be sure to properly cap all lines

17
Q

Cylinder barrels that are heavily damaged must be?

A

Replaced or retubed

18
Q

Cylinder barrel that is lightly scored can be refinished by?

A

Honing the inside diameter of the barrel

19
Q

How do you measure a cylinder barrel?

A

Take measurements at 2 points 90° apart down the full length of the barrel

20
Q

What should cylinder rod be visually check for?

A

Bending cracking and damage to the cylinder rod surface

21
Q

What’s the best way to check rod straightness

A

Rotate the rod on v blocks and use a dial indicator to measure the deflection