Steering and Suspension Flashcards

What is the thrust angle on a vehicle?

Answer: The angle between the vehicle's geometric centreline and the direction the rear wheels point

The thrust angle is the direction the rear wheels are actually pushing the vehicle, compared to the geometric centreline. If the rear wheels are not parallel to the centreline, the vehicle will 'dog track' (drive at an angle).

What is the function of the steering gear preload adjustment?

Answer: To set the proper drag on the steering gear to eliminate free play while maintaining smooth operation

Steering gear preload sets the bearing or mesh tension to eliminate excessive free play (dead spot) at the centre of steering travel while ensuring the gear operates smoothly without binding.

What type of suspension uses a single pivoting arm to locate the rear wheel?

Answer: Trailing arm suspension

A trailing arm suspension uses a single arm that pivots from a point ahead of the wheel and trails rearward to the wheel hub, controlling wheel movement in the vertical plane. It is commonly used on rear non-driven axles.

What does a lateral pull during straight-line driving (not during braking) most commonly indicate?

Answer: Unequal caster angles between the left and right front wheels

The vehicle pulls toward the side with less positive caster. Unequal caster side-to-side is the primary alignment angle that causes a constant pull during straight-line driving. Cross-camber and tire condition are secondary factors.

What is the purpose of the compliance bushings in a suspension system?

Answer: To allow controlled deflection of suspension arms for ride comfort while maintaining alignment geometry

Compliance bushings are made of rubber or polyurethane and allow small, controlled movements of suspension arms. They absorb impacts, reduce NVH (noise, vibration, harshness), and maintain alignment within acceptable limits.

A technician is measuring rear toe on an independent rear suspension vehicle and finds excessive toe-out on one side. What is the most likely cause?

Answer: A worn or damaged rear control arm bushing or bent rear control arm

On independent rear suspension, rear toe is set by the position of the rear control arms. Worn bushings allow the arm to shift, and a bent arm directly changes the toe angle, both causing toe-out.