Steering and Suspension Systems Flashcards

What does Ackermann steering geometry ensure during a turn?

Answer: The inside front wheel turns at a greater angle than the outside wheel

Ackermann geometry angles the inside wheel more sharply so both front wheels can follow their own turning radius without tire scrub.

A technician notices the air pressure in one air spring on a rear tag axle is significantly lower than the other side. What is the MOST likely result?

Answer: Uneven load distribution causing axle thrust angle change

Unequal air spring pressure causes one side of the axle to ride lower, shifting the axle and altering its thrust angle relative to the vehicle centerline.

When a hydraulic power steering pump is pressure-tested and output pressure is low at idle but reaches spec when the engine speed is increased, what is indicated?

Answer: A worn or faulty flow control valve

A worn flow control valve allows flow to bypass at low pump speeds, reducing pressure at idle while higher RPM compensates through increased volume.

What is the function of the king pin inclination (KPI) angle?

Answer: Provides directional stability by creating a self-centering effect and reducing steering effort

KPI creates a geometric pivot that causes the front of the vehicle to lift slightly in a turn, providing a self-centering force and reducing steering effort.

A coach steering system uses an electric power steering (EPS) assist. The driver reports steering assist is present at low speeds but disappears at highway speeds. This is:

Answer: Normal operation — EPS reduces assist as speed increases for better road feel

EPS systems are speed-sensitive by design, providing maximum assist at low speeds and progressively reducing assist at higher speeds to improve stability and road feel.

Feathered (saw-tooth) wear across the face of a tire tread is a diagnostic indicator of:

Answer: Incorrect toe adjustment

Feathered wear, where tread blocks are worn sharp on one edge and rounded on the other, is caused by incorrect toe setting (toe-in or toe-out).

What is the purpose of the drag link in a conventional truck steering system?

Answer: Transmits steering motion from the pitman arm to the steering knuckle or tie rod

The drag link connects the pitman arm (output of the steering gear) to the steering knuckle arm or cross-tube, transmitting the steering input to the front wheels.