Heavy Equipment

Question 1

What are the two main types of hydraulic systems?

Answer 1

Open-center systems
Closed-center systems

Question 2

Explain the seven steps in diagnosing a problem

Answer 2

1. Know the system
2. ask the operator
3. operate the machine
4. inspect the machine
5. List the possible causes
6. Reach a conclusion
7. Test your conclusion

Question 3

What does a service technician do?

Answer 3

• Trouble shooter
• collects facts and pinpoints the trouble before doing any repairs

Question 4

What does a parts changer do?

Answer 4

Dives into the machine and starts replacing parts until the trouble is found rather than diagnosing the issue first

Question 5

What are the 4 primary things that require testing in a hydraulic circuit?

Answer 5

1. Pressure
2. Flow
3. Speed (leakage)
4. Temperature

Question 6

What are the simple leakage tests that can be performed without test equipment?

Answer 6

Checking both hydraulic cylinders to see if there is a significant difference in the heat.

Question 7

Faulty circuit relief valves will affect _______

Answer 7

only pressure readings in the individual circuits

Question 8

What check should be made before testing or repairing a leak?

Answer 8

You should make sure all hydraulic oil pressure is drained from the system and that all increments are secured to the ground.

Question 9

What is the principal of the “operational checkout”?

Answer 9

Look, listen, feel

Question 10

Faulty system relief valves will affect ______

Answer 10

readings in all tests

Question 11

What is the condition of the machine if the flow readings are the same as the pump readings?

Answer 11

The pump is working fine and all components are okay

Question 12

What is the condition of the machine if flow drops as maximum pressure us reached with the control valve in all positions?

Answer 12

The system relief valve is probably at fault

Question 13

There are ________ basic steps in a diagnostic-testing program.

Answer 13

7

Question 14

The basic checks that can be made with most hydraulic testers is temperature, flow, ___________ and ___________.

Answer 14

pressure and leakage

Question 15

When high pressure can not be reached in all the circuits of an open-centre system, the problem is most likely _______

Answer 15

a system relief valve

Question 16

When testing pump and component flow, it is important that _______ and _______ remain constant

Answer 16

temperatures and engine speeds

Question 17

What are the two general rules for the effect of relief valves on the system?

Answer 17

1. Faulty system relief valves will affect readings in all tests
2. Faulty circuit relief valves will affect only pressure readings in the individual circuits

Question 18

Internal leakage in a hydraulic motor can be checked by measuring the amount of oil flowing from __________

Answer 18

the drain line when the motor is at full load

Question 19

_______ temperature is an important factor to consider when performing hydraulic test

Answer 19

Hydraulic oil