CFA Hydraulic & Transmission Service 3 — Questions and Answers
Question 1: What is the function of a hydraulic flow control valve in a forklift's lowering circuit?
- To increase the speed at which the mast raises
- To regulate the descent speed of the forks regardless of load weight (Correct answer)
- To prevent the forks from raising beyond maximum height
- To filter hydraulic fluid during the lowering cycle
Correct answer: To regulate the descent speed of the forks regardless of load weight
A flow control valve meters the fluid leaving the lift cylinder during lowering, maintaining a controlled descent speed whether the load is heavy or light.
Question 2: Hydraulic hoses on a forklift should be inspected for all of the following EXCEPT:
- Cracks, abrasions, and cuts in the outer cover
- Bulges or soft spots indicating inner liner failure
- Color fading due to UV exposure over time (Correct answer)
- Loose or corroded fittings at connection points
Correct answer: Color fading due to UV exposure over time
While hose condition is critical, color fading from UV exposure alone is cosmetic and not a safety defect; structural damage and fitting integrity are the key inspection points.
Question 3: In a hydrostatic transmission forklift, what controls travel speed and direction?
- A gearshift lever and manual clutch pedal
- Variable displacement hydraulic pump and motor (Correct answer)
- A torque converter and planetary gear set
- Electronic solenoids and a fixed-ratio gear set
Correct answer: Variable displacement hydraulic pump and motor
Hydrostatic transmissions use a variable displacement pump to control both speed and direction by varying fluid flow and direction to the hydraulic drive motor.
Question 4: What is the most common cause of hydraulic cylinder drift (slow unintended lowering of the load)?
- Hydraulic pump cavitation
- Worn or damaged cylinder piston seals (Correct answer)
- Clogged hydraulic filter
- Low engine idle speed
Correct answer: Worn or damaged cylinder piston seals
Worn piston seals allow hydraulic fluid to bypass the piston, causing the cylinder to slowly retract under load even when the control valve is in neutral.
Question 5: A forklift's transmission fluid should be changed at intervals specified in the:
- OSHA 1910.178 regulation handbook
- Manufacturer's service and maintenance manual (Correct answer)
- ANSI B56.1 safety standard
- Daily pre-shift inspection checklist
Correct answer: Manufacturer's service and maintenance manual
Transmission fluid change intervals are specified by the forklift manufacturer in the service manual and vary by model, application, and operating conditions.
Question 6: Which condition would cause hydraulic fluid to overheat during normal operation?
- Operating the forklift in cold weather below 32°F
- A clogged hydraulic filter restricting fluid flow (Correct answer)
- Checking fluid level with the engine off
- Using the correct manufacturer-specified hydraulic fluid
Correct answer: A clogged hydraulic filter restricting fluid flow
A clogged filter creates excessive flow restriction, causing the pump to work harder and generating heat as fluid is forced through the blockage.
Question 7: What is the purpose of the hydraulic system's breather cap on the reservoir?
- To pressurize the reservoir for faster pump priming
- To allow air exchange while preventing contamination from entering (Correct answer)
- To measure the current hydraulic fluid temperature
- To automatically add fluid when the level drops
Correct answer: To allow air exchange while preventing contamination from entering
The breather cap allows the reservoir to breathe as fluid levels change while its filter prevents dirt and moisture from contaminating the hydraulic fluid.
CFA Hydraulic & Transmission Service 3
What is the function of a hydraulic flow control valve in a forklift's lowering circuit?