SOS Mechanic Certification Test: Suspension &
steering – Questions With All Correct Solutions
1. Bleeding a power steering unit is generally done by
Answer: turning the steering wheel left and right repeatedly
Rationale: Turning the wheel lock-to-lock forces air out of the fluid and allows fresh
fluid to circulate, which is the standard manual bleeding procedure.
2. After rounding a turn, the front wheels do not return to the straight ahead position
in a normal way. What adjustment is most likely to be out of specifications?
Answer: Caster
Rationale: Caster provides the self-centering effect; insufficient caster prevents the
wheels from returning to center after a turn.
3. "Toe" adjustment on front wheel drive vehicles is made by:
Answer: changing the length of the steering linkage
Rationale: On FWD vehicles with rear toe adjustment only, front toe is typically set
by adjusting the tie rod lengths on the steering linkage.
4. When performing a front-end alignment what should you do before you adjust the
toe setting?
Answer: adjust the caster & camber
Rationale: Caster and camber affect toe angle; toe should always be adjusted last in
a standard alignment sequence.
5. Front-wheel toe-in adjustment on rear-wheel drive vehicles is made by:
Answer: changing the length of the steering linkage
Rationale: Regardless of drive type, toe is adjusted by altering tie rod length on rack-
and-pinion or parallelogram systems.
6. A mechanic is going to adjust the curb height on a car with torsion bars. To do this
the car should be checked:
Answer: on a level surface with the car at curb weight
, Rationale: Curb height (ride height) must be measured under normal vehicle load
and on a level surface for accuracy.
7. A proper way to check ball joints for wear is by:
Answer: visual observation of the wear indicator & unloading the ball joint
and using a pry bar and a dial indicator
Rationale: Both methods are used: some ball joints have wear indicators, and others
require unloading and prying to measure play.
8. Which of the following adjustments can be made on all vehicles with MacPherson
strut suspensions?
Answer: Toe settings
Rationale: Many MacPherson strut designs allow only toe adjustment unless
camber/caster kits are installed; toe is universally adjustable.
9. A vehicle with rack-and-pinion steering has excessive free play in the steering
wheel. What is the most common cause?
Answer: Worn inner or outer tie rod ends
Rationale: Tie rod ends are the most common wear points in rack-and-pinion
systems, creating free play before the gear itself fails.
10. What is the primary purpose of a power steering pressure switch?
Answer: To signal the engine computer to increase idle speed during parking
maneuvers
Rationale: When the steering is turned against the stop, pressure rises; the switch
tells the PCM to raise idle to prevent stalling.
11. Which alignment angle is not adjustable on most solid rear axle vehicles?
Answer: Camber
Rationale: Solid rear axles typically have fixed camber and toe (toe may be
adjustable with shims or eccentric bolts on some).
12. A customer complains of a "shimmy" at highway speeds that goes away when
accelerating or braking. What is the most likely cause?
Answer: Wheel imbalance
, Rationale: Imbalance causes vibration at specific speeds; acceleration/braking
changes load and may temporarily mask the shimmy.
13. What is the correct procedure to check for a worn steering rack mounting
bushings?
Answer: Have an assistant turn the steering wheel while observing rack
movement relative to the subframe
Rationale: Worn bushings allow the entire rack to move side to side, causing loose
steering feel and poor centering.
14. A vehicle pulls to the right while driving on a level road. After rotating tires, it still
pulls right. What should be checked next?
Answer: Caster and camber angles
Rationale: Tire rotation rules out tire pull; alignment angles (especially cross-camber
or cross-caster) are the next likely cause.
15. What is the function of a strut bearing plate (upper strut mount)?
Answer: Allows the strut to pivot during steering while supporting vehicle
weight
Rationale: The bearing plate sits between the strut and body, enabling smooth
turning and absorbing road shocks.
16. When replacing inner tie rod ends on a rack-and-pinion, why must the rack be
supported?
Answer: To prevent damage to the rack internal bushings or housing
Rationale: Applying leverage without support can crack the rack housing or damage
internal components.
17. What is the most likely symptom of a worn pitman arm?
Answer: Excessive play in the steering wheel and wandering
Rationale: The pitman arm connects the steering gear to the center link; wear creates
lost motion and directional instability.
18. A vehicle has uneven front tire wear on the inside edges only. What alignment
angle is most likely at fault?
Answer: Excessive negative camber
, Rationale: Negative camber tilts the top of the wheel inward, causing inside edge
wear.
19. How does a variable assist power steering system work?
Answer: It reduces assist at highway speeds for better feel and increases assist
at low speeds for easier parking
Rationale: A solenoid or valve modulates fluid pressure based on vehicle speed.
20. What is the purpose of a toe plate gauge?
Answer: To measure total toe without using a full alignment machine
Rationale: A toe plate is a simple tool placed against the tires to measure the
difference in distance between front and rear of tires.
21. A vehicle with electronic power steering (EPS) has no assist but no warning lights.
What should be tested first?
Answer: Power and ground circuits to the EPS motor
Rationale: Electrical supply issues are common; lack of assist with no codes often
points to a blown fuse or bad relay.
22. When performing a dry park test, the technician turns the steering wheel side to
side with the engine off. What is being checked?
Answer: Loose or worn steering and suspension components
Rationale: Without power assist, play in joints becomes easier to feel and see.
23. What is the correct torque sequence for tightening a steering knuckle pinch bolt?
Answer: Tighten to manufacturer specification; no specific sequence needed
for a single bolt
Rationale: Pinch bolts are usually single fasteners; follow torque spec to avoid
stripping or breaking.
24. A vehicle has a loose, wandering feel at highway speeds. Alignment is within spec.
What is the most likely cause?
Answer: Worn idler arm or pitman arm
Rationale: Worn steering linkage components cause vagueness even when alignment
angles are correct.
steering – Questions With All Correct Solutions
1. Bleeding a power steering unit is generally done by
Answer: turning the steering wheel left and right repeatedly
Rationale: Turning the wheel lock-to-lock forces air out of the fluid and allows fresh
fluid to circulate, which is the standard manual bleeding procedure.
2. After rounding a turn, the front wheels do not return to the straight ahead position
in a normal way. What adjustment is most likely to be out of specifications?
Answer: Caster
Rationale: Caster provides the self-centering effect; insufficient caster prevents the
wheels from returning to center after a turn.
3. "Toe" adjustment on front wheel drive vehicles is made by:
Answer: changing the length of the steering linkage
Rationale: On FWD vehicles with rear toe adjustment only, front toe is typically set
by adjusting the tie rod lengths on the steering linkage.
4. When performing a front-end alignment what should you do before you adjust the
toe setting?
Answer: adjust the caster & camber
Rationale: Caster and camber affect toe angle; toe should always be adjusted last in
a standard alignment sequence.
5. Front-wheel toe-in adjustment on rear-wheel drive vehicles is made by:
Answer: changing the length of the steering linkage
Rationale: Regardless of drive type, toe is adjusted by altering tie rod length on rack-
and-pinion or parallelogram systems.
6. A mechanic is going to adjust the curb height on a car with torsion bars. To do this
the car should be checked:
Answer: on a level surface with the car at curb weight
, Rationale: Curb height (ride height) must be measured under normal vehicle load
and on a level surface for accuracy.
7. A proper way to check ball joints for wear is by:
Answer: visual observation of the wear indicator & unloading the ball joint
and using a pry bar and a dial indicator
Rationale: Both methods are used: some ball joints have wear indicators, and others
require unloading and prying to measure play.
8. Which of the following adjustments can be made on all vehicles with MacPherson
strut suspensions?
Answer: Toe settings
Rationale: Many MacPherson strut designs allow only toe adjustment unless
camber/caster kits are installed; toe is universally adjustable.
9. A vehicle with rack-and-pinion steering has excessive free play in the steering
wheel. What is the most common cause?
Answer: Worn inner or outer tie rod ends
Rationale: Tie rod ends are the most common wear points in rack-and-pinion
systems, creating free play before the gear itself fails.
10. What is the primary purpose of a power steering pressure switch?
Answer: To signal the engine computer to increase idle speed during parking
maneuvers
Rationale: When the steering is turned against the stop, pressure rises; the switch
tells the PCM to raise idle to prevent stalling.
11. Which alignment angle is not adjustable on most solid rear axle vehicles?
Answer: Camber
Rationale: Solid rear axles typically have fixed camber and toe (toe may be
adjustable with shims or eccentric bolts on some).
12. A customer complains of a "shimmy" at highway speeds that goes away when
accelerating or braking. What is the most likely cause?
Answer: Wheel imbalance
, Rationale: Imbalance causes vibration at specific speeds; acceleration/braking
changes load and may temporarily mask the shimmy.
13. What is the correct procedure to check for a worn steering rack mounting
bushings?
Answer: Have an assistant turn the steering wheel while observing rack
movement relative to the subframe
Rationale: Worn bushings allow the entire rack to move side to side, causing loose
steering feel and poor centering.
14. A vehicle pulls to the right while driving on a level road. After rotating tires, it still
pulls right. What should be checked next?
Answer: Caster and camber angles
Rationale: Tire rotation rules out tire pull; alignment angles (especially cross-camber
or cross-caster) are the next likely cause.
15. What is the function of a strut bearing plate (upper strut mount)?
Answer: Allows the strut to pivot during steering while supporting vehicle
weight
Rationale: The bearing plate sits between the strut and body, enabling smooth
turning and absorbing road shocks.
16. When replacing inner tie rod ends on a rack-and-pinion, why must the rack be
supported?
Answer: To prevent damage to the rack internal bushings or housing
Rationale: Applying leverage without support can crack the rack housing or damage
internal components.
17. What is the most likely symptom of a worn pitman arm?
Answer: Excessive play in the steering wheel and wandering
Rationale: The pitman arm connects the steering gear to the center link; wear creates
lost motion and directional instability.
18. A vehicle has uneven front tire wear on the inside edges only. What alignment
angle is most likely at fault?
Answer: Excessive negative camber
, Rationale: Negative camber tilts the top of the wheel inward, causing inside edge
wear.
19. How does a variable assist power steering system work?
Answer: It reduces assist at highway speeds for better feel and increases assist
at low speeds for easier parking
Rationale: A solenoid or valve modulates fluid pressure based on vehicle speed.
20. What is the purpose of a toe plate gauge?
Answer: To measure total toe without using a full alignment machine
Rationale: A toe plate is a simple tool placed against the tires to measure the
difference in distance between front and rear of tires.
21. A vehicle with electronic power steering (EPS) has no assist but no warning lights.
What should be tested first?
Answer: Power and ground circuits to the EPS motor
Rationale: Electrical supply issues are common; lack of assist with no codes often
points to a blown fuse or bad relay.
22. When performing a dry park test, the technician turns the steering wheel side to
side with the engine off. What is being checked?
Answer: Loose or worn steering and suspension components
Rationale: Without power assist, play in joints becomes easier to feel and see.
23. What is the correct torque sequence for tightening a steering knuckle pinch bolt?
Answer: Tighten to manufacturer specification; no specific sequence needed
for a single bolt
Rationale: Pinch bolts are usually single fasteners; follow torque spec to avoid
stripping or breaking.
24. A vehicle has a loose, wandering feel at highway speeds. Alignment is within spec.
What is the most likely cause?
Answer: Worn idler arm or pitman arm
Rationale: Worn steering linkage components cause vagueness even when alignment
angles are correct.
