301E: Hydraulic Actuator Service Flashcards
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)
True
301E
How would a hydraulic cylinder operate if the lines are reversed from their original position?
The cylinder will function opposite to normal operation
301E
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)
False
301E
A rough determination of cylinder rod straightness can be made by using a straight edge. A more accurate determination is made by:
Rrotating the cylinder rod while it is supported in V-blocks and reading the amount of deflection on a dial indicator.
301E Pg. 9
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)
True
301E
What contributing causes should be considered when analyzing a hydraulic motor failure? (7)
- Condition of each motor part
- Type and condition of hydraulic oil and filters
- Operating conditions and symptoms before failure
- Conditions of other hydraulic system components
- Severity of job application
- Hours on the motor
- Previous failures and repairs
301E Pg. 17
Which of the following is not evidence that a hydraulic motor has failed due to lack of lubrication?
a) Heavy wear on the surfaces of moving parts
b) Blue coloring
c) Smearing and metal transfer between contacting surfaces
d) Pitted erosion and motor components
Pitted erosion on motor components - cavitation
301E Pg. 21
What start-up procedures should be observed after a hydraulic motor is installed? (4)
- Back off system pressure controls
- Operate the motor at no load and check for leaks or unusualnnoises
- Apply a load to the motor and warm up the hydraulic oil. Adjust system pressure controls
- Perform operational tests to confirm that the machine is performing satisfactorily
301E Pg. 22
Lack of lubrication in a hydraulic motor is usually caused by: (3)
- Improper hydraulic oil
- Low reservoir oil
- Severe aeration
301E Pg. 20
You are inspecting a hydraulic pump that you suspect failed due to lack of lubrication. What would indicate that lack of lubrication was the cause? (4)
- Heavy wear on moving surfaces.
- Blue coloring, indicating an overheat condition.
- Smearing and metal transfer.
- Motor seizure in severe cases.
301E Pg. 20
Cylinder barrels that are lightly scored can be refinished by:
Honing the inside diameter of the barrel
301E Pg. 7
How would you measure a cylinder barrel durring an inspection?
Measure for wear and out of round.
Using a cylinder bore gauge, take measurements at 2 points 90° apart down the full length of the barrel.
301E Pg. 8
What should cylinder rods be visually check for?
- Bending
- Cracking
- Damage to the rod surface
301E Pg. 8
Cylinder barrels that are heavily damaged must either be replaced or:
Retubed
301E Pg. 7
Upon inspecting a hydraulic motor, you find it has components that appear sandblasted or dull, particularly on pressure plates, bearings, and shafts. What is most likely the cause?
Having operated with contaminated oil for a long period of time.
301E Pg. 18
