Hydraulic Systems Testing Flashcards
190301h
What is the first thing to check when dealing with a machine that has hydraulic issues?
Fluid reservoir level.
Without having any engine specs, how would a tech find hydraulic pump efficiency?
Take pump flow readings at no load, and at relief pressure. The math is: (relief pressure flow/no load pressure flow)x100. Any less than 80% is a failed pump.
How is cycle times tested?
Record the amount of time taken to full stroke an actuator and compare it to manufacturers specification.
Why is snubbing used in hydraulic pressure gauges?
To ensure the needle stays consistent so it can be properly read.
If a hydraulic system is found to be operating at proper pump flow but when sent over relief the engine droops out of spec, what could be the cause?
Pressure relief settings may have been set higher than manufacturer spec.
What does a PSIA gauge read?
Pounds per square inch plus atmosphere.
What care should be taken before cracking into a hydraulic system?
Ensure that pressure is relieved in the system.
With the engine at wide open throttle and an implement dead headed at full stroke what pressure is the technician checking?
Full flow relief pressure.
What is a ‘T’ test used to check?
With the flow valve restriction set slightly less than system relief, The ‘T’ test is used to find components leaking elsewhere in the system.
What is this test configuration called? (Hint: Leakage test)
‘T’ test.
If all cycle times have failed where should the tech look before digging into the hydraulic pump system?
Ensure proper engine RPM is achieved for testing.
What pressure gauge range should be selected when testing a hydraulic system?
Ideal testing gauge will be twice that of system specification.
