Free 310T Steering and Suspension Systems Questions and Answers — Questions and Answers
Question 1: A driver reports a condition known as 'memory steer,' where the truck continues to pull to one side after a turn and must be manually corrected. Which of the following is the MOST likely cause of this symptom?
- A worn steering damper
- Binding kingpins (Correct answer)
- Excessive positive caster
- Low power steering fluid
Correct answer: Binding kingpins
Memory steer occurs when steering components bind, preventing the natural self-centering action of the steering geometry. Binding or overly tight kingpins are a primary cause, as they introduce excessive friction into the steering knuckle's pivot points, overcoming the caster angle's ability to return the wheels to a straight-ahead position.
Question 2: Which of the following wheel alignment angles has the primary responsibility for creating directional stability and promoting steering wheel returnability after a turn?
- Camber
- Toe
- Caster (Correct answer)
- Thrust Angle
Correct answer: Caster
Caster is the forward or rearward tilt of the steering axis when viewed from the side. A positive caster angle positions the tire's contact patch behind the steering axis pivot, creating a self-aligning torque that helps the vehicle maintain a straight path and causes the steering wheel to return to center.
Question 3: What is the primary function of a height control valve in a heavy-duty truck's air suspension system?
- To regulate the pressure of the air compressor.
- To automatically maintain a predetermined ride height regardless of the load. (Correct answer)
- To control the firmness of the shock absorbers.
- To manually release air from the system for maintenance.
Correct answer: To automatically maintain a predetermined ride height regardless of the load.
The height control valve is mechanically linked to the axle and frame. It senses changes in the distance between them due to loading or unloading and automatically adds or removes air from the air springs (bellows) to maintain a constant, preset ride height.
Question 4: During a 'dry park check,' an assistant rocks the steering wheel back and forth while the truck's full weight is on the ground. The technician observes vertical (up-and-down) movement in the drag link where it connects to the steering arm. This observation indicates:
- A worn pitman arm
- Loose steering gear mounting bolts
- A worn drag link socket (Correct answer)
- Normal component movement
Correct answer: A worn drag link socket
A dry park check is designed to identify looseness in steering components under normal load. Rotational or horizontal movement in the drag link is normal, but any vertical play within the ball-and-socket joint indicates excessive wear. The component with vertical play must be replaced.
Question 5: A technician observes severe cupping, or scalloped wear, on both steer axle tires. Which of the following conditions is the MOST likely cause?
- Incorrect toe setting
- Worn or failing shock absorbers (Correct answer)
- Excessive axle thrust angle
- Over-inflated tires
Correct answer: Worn or failing shock absorbers
Tire cupping is a wear pattern of high and low spots caused by the tire bouncing and not maintaining consistent contact with the road. The most common cause is worn shock absorbers that can no longer dampen suspension oscillations, allowing the tire to hop on the road surface.
Question 6: On a tandem-axle suspension, what is the main purpose of longitudinal and transverse torque rods?
- To support the vertical load of the vehicle.
- To absorb road vibrations for a smoother ride.
- To provide a mounting point for the air springs.
- To control axle positioning and absorb braking and acceleration forces. (Correct answer)
Correct answer: To control axle positioning and absorb braking and acceleration forces.
Torque rods are critical links that connect the axle housing to the frame. They prevent the axle from rotating during acceleration and braking (axle wrap) and also maintain the axle's lateral and longitudinal alignment, which is essential for proper handling and driveline angles.
Free 310T Steering and Suspension Systems Questions and Answers
A driver reports a condition known as 'memory steer,' where the truck continues to pull to one side after a turn and must be manually corrected.
Which of the following is the MOST likely cause of this symptom?