OECP Hydraulic Systems & Pneumatics 2

Question 1

What is the recommended method for checking hydraulic fluid level in heavy construction equipment?

Accepted Answer

Check the sight glass or dipstick with the machine on level ground and cylinders retracted

Answer

Check the reservoir sight glass with the engine running at full RPM

Answer

Check the fluid level immediately after shutdown while fluid is still hot

Answer

Check the reservoir only when all hydraulic cylinders are fully extended

Question 2

What does a milky or foamy appearance in hydraulic fluid most likely indicate?

Accepted Answer

Water contamination has entered the hydraulic system

Answer

The fluid is overheating due to excessive continuous load cycles

Answer

The fluid viscosity rating is too high for current operating temperatures

Answer

Metal particles from a failing pump have entered the fluid

Question 3

What is the primary cause of hydraulic system overheating during equipment operation?

Accepted Answer

Continuous operation with a partially open or bypassing relief valve

Answer

Using hydraulic fluid with a viscosity rating that is too low

Answer

Operating equipment at low ambient temperatures below freezing

Answer

Using filters with too fine a micron rating for the application

Question 4

When replacing hydraulic filters, what is the most critical safety precaution that must be taken first?

Accepted Answer

Relieve all system pressure and wear appropriate PPE before removing any filter

Answer

Run the engine at high idle to purge air from the new filter element

Answer

Drain the entire hydraulic reservoir to prevent any contamination during the change

Answer

Always replace the hydraulic fluid at the same time as the filter for best results

Question 5

What is the primary function of a hydraulic accumulator in a heavy equipment system?

Accepted Answer

To store hydraulic energy and dampen pressure surges

Answer

To measure and record total system pressure output over time

Answer

To regulate and maintain constant hydraulic fluid temperature

Answer

To separate entrained air from circulating hydraulic fluid

Question 6

Which type of contamination is generally considered most damaging to hydraulic system components?

Accepted Answer

Particulate (solid) contamination from dirt, wear debris, or seal material

Answer

Water contamination from condensation in the reservoir

Answer

Air contamination from a loose suction line fitting

Answer

Chemical contamination from incompatible fluid mixing

Question 7

What action must be taken when a hydraulic hose shows visible signs of abrasion, chafing, or bulging?

Accepted Answer

Remove the equipment from service immediately and replace the damaged hose

Answer

Apply hydraulic sealant compound to the damaged area and monitor during operation

Answer

Wrap the damaged section with hydraulic hose tape as a temporary field repair

Answer

Reduce system operating pressure by 25% to extend the hose's remaining service life