190301e

Question 1

A quick method to check for internal leakage in a double-acting cylinder is to stall the cylinder, remove the return line and ____________________________

Answer 1

measure the amount of oil flowing past the
piston seals

Question 2

What would happen if cylinder hydraulic lines were reversed from their original position when the cylinder was installed?

Answer 2

the cylinder would function opposite to normal operation

Question 3

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

Answer 3

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

Question 4

It is possible to remove the damaged chrome surface from a cylinder rod and replace it with new material using an _____________ process

Answer 4

electroplating

Question 5

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

Answer 5

1) the condition of each motor part
2) type and condition of hydraulic oil and filters
3) operating conditions and symptoms before failure
4) conditions of other hydraulic system components

Question 6

What is not evidence that a hydraulic motor has failed due to lack of lubrication?

Answer 6

pitted erosion on motor components

Question 7

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

Answer 7

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

Question 8

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

Answer 8

Improper hydraulic oil
Low reservoir oil
Severe aeration

Question 9

What evidence would you see that would indicate a lack of lubrication?

Answer 9

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

Question 10

Why is cleanliness is critical for hydraulic pump motors?

Answer 10

Because of low clearances and low tolerances for contamination.

Question 11

True or False: Certain shafts need to be lubricated before installation

Answer 11

True

Question 12

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

Answer 12

1. Back off the system pressures prior to start up.
2. Operate at no load checking for leaks and unusual noises.
3. Apply a load to the motor and warm the oil to operating temperatures. Then set relief.
4. Perform operational tests and check cycle times.

Question 13

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

Answer 13

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

Question 14

What should be done about cylinder barrels that are heavily damaged?

Answer 14

Replaced or retubed

Question 15

How can you refinish a cylinder barrel that is lightly scored?

Answer 15

Honing the inside diameter of the barrel

Question 16

How do you measure a cylinder barrel?

Answer 16

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

Question 17

What should cylinder rod be visually check for?

Answer 17

Bending cracking and damage to the cylinder rod surface

Question 18

What’s the best way to check rod straightness?

Answer 18

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