190301e 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
If cylinder hydraulic lines are reversed from their original position when the cylinder
is installed:
the cylinder will function opposite to normal operation.
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;
A rough determination of cylinder rod straightness can be made by using a straight
edge. A more accurate determination is made by:
rotating the cylinder rod while it is supported in V-blocks and reading the amount of
deflection on a dial indicator.
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
In order to completely analyze a hydraulic motor failure, you must consider several
contributing causes. List four (4).
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
Which of the following is not evidence that a hydraulic motor has failed due to lack
of lubrication?
pitted erosion on motor components
List four (4) start-up procedures that should be observed after a hydraulic motor is installed
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.
What are the ways that a lack of lubrication may occur in a motor?
Improper hydraulic oil
Low reservoir oil
Severe aeration
What is the lack of lubrication evidence?
Heavy wear on moving surfaces.
Blue coloring, indicating an overheat condition.
Smearing and metal transfer.
Motor seizure in severe cases.
Cleanliness is critical for hydraulic pump motors. T/F
True. Because of low clearances and low tolerances for contamination.
You should check for motor driveshaft wear and misalignment. T/F
True
Certain shafts need to be lubricated before installation. T/F
True.
What are 4 main start up procedures for when you have installed a motor?
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.
Hydraulic motors can be large and heavy and are sometimes mounted in awkward locations, what are some precautions we should take? (2)
Use hoists and lifting equipment wherever possible and use proper manual lifting techniques when required.
