NAPA - National Automotive Parts Association Certified Mechanic Suspension and Steering Questions and Answers

Question 1

A vehicle is brought in with a clunking noise from the front end, most noticeable during low-speed turns and when driving over bumps. The driver also reports that the steering feels loose. Which of the following is the MOST likely cause?

Accepted Answer

Worn ball joints

Answer

Worn ball joints are a common cause of clunking or rattling noises from the front suspension, especially over bumps or during turns. The excessive play in a worn joint also leads to a loose or wandering steering feel. While sway bar links can cause noise, they typically don't affect steering feel as dramatically. A failing power steering pump would cause whining noises and stiff steering, not clunking. Incorrect tire pressure primarily affects pulling and tire wear.

Question 2

A technician is performing a wheel alignment and finds the caster angle is significantly more positive on the left front wheel than on the right. What is the MOST likely effect this will have on the vehicle's handling?

Accepted Answer

The vehicle will pull to the left.

Answer

Caster is the forward or rearward tilt of the steering axis. A more positive caster angle provides greater straight-line stability. When caster angles are unequal side-to-side, the vehicle will pull toward the side with the LEAST amount of positive caster. In this case, with the left side being more positive, the vehicle will pull to the right.

Question 3

Which of the following is NOT a primary component of a typical MacPherson strut assembly?

Accepted Answer

Control arm

Answer

A MacPherson strut assembly is a single unit that typically includes the shock absorber (damper), coil spring, and an upper strut mount with a bearing. The control arm is a separate suspension component that connects the bottom of the steering knuckle to the vehicle's frame or subframe.

Question 4

A customer complains of a whining or groaning noise that gets louder when turning the steering wheel, especially at low speeds. The steering also feels unusually stiff. What is the MOST probable cause of these symptoms?

Accepted Answer

A failing power steering pump

Answer

A whining or groaning noise during steering, combined with stiff steering effort, are classic symptoms of a failing power steering pump. This can be due to low fluid levels, air in the system, or internal wear within the pump itself. Worn tie rods cause looseness and noise but not typically whining. Low tire pressure and poor alignment cause pulling or uneven tire wear.

Question 5

In a rack and pinion steering system, what is the primary function of the inner tie rod?

Accepted Answer

To connect the steering rack to the outer tie rod, transferring steering inputs.

Answer

The inner tie rod acts as a pivot and connects the movable steering rack to the outer tie rod end. When the driver turns the wheel, the rack moves side-to-side, pushing or pulling the inner tie rod, which in turn moves the outer tie rod and the steering knuckle to turn the wheels. Shock absorbers handle impacts, and caster is adjusted at the control arms or strut mounts. The sway bar controls body roll.

NAPA - National Automotive Parts Association Certified Mechanic Practice Test

NAPA - National Automotive Parts Association Certified Mechanic Practice Test

NAPA - National Automotive Parts Association Certified Mechanic Suspension and Steering Questions and Answers