Steering and Suspension Flashcards

What type of power steering system uses an electric motor instead of a hydraulic pump?

Answer: Electric power steering (EPS)

Electric power steering (EPS) uses an electric motor mounted on the steering column or rack to provide steering assist. It eliminates the hydraulic pump, hoses, and fluid, improving fuel efficiency and enabling advanced driver-assist features.

What does a worn outer tie rod end typically cause?

Answer: Loose steering feel, wandering, and accelerated toe-related tire wear

A worn outer tie rod end introduces play in the steering linkage, causing loose steering, wandering at highway speeds, and loss of proper toe alignment, leading to feathered or scuffed tire wear patterns.

When performing a ball joint inspection, what indicates a worn load-carrying ball joint on a short-long arm (SLA) suspension?

Answer: Excessive axial (vertical) play measured with the suspension unloaded (wheel raised off the ground) using a dial indicator

Load-carrying ball joints must be unloaded for inspection. On an SLA suspension, the lower ball joint typically carries the load, so the wheel is raised and a dial indicator measures vertical play at the joint.

What is the purpose of the power steering pressure switch?

Answer: To signal the ECM to increase idle speed when steering load is high to prevent stalling

When the power steering system is under high load (such as during parking manoeuvres), the pressure switch signals the ECM to increase idle speed, compensating for the additional load on the engine from the power steering pump.

What causes cupping (scalloped wear) on tires?

Answer: Worn shock absorbers or struts allowing the tire to bounce and lose contact with the road

Cupping occurs when worn dampers (shock absorbers or struts) fail to keep the tire in consistent contact with the road. The tire bounces, creating a pattern of high and low spots around the tread surface.

What is the function of the upper strut mount (bearing plate)?

Answer: To allow the strut assembly to pivot when the steering wheel is turned while isolating suspension noise from the body

The upper strut mount attaches the strut to the body and contains a bearing that allows the strut to rotate when steering. It also includes rubber isolation to prevent road noise and vibration from transferring to the body.