Power Steering and 4 Wheel Steering

Question 1

Why do we not have full power steering and only assisted?

Answer 1

If power fails then steering will also fail

Question 2

What must PAS systems be?

Answer 2

• Fail safe

- Assistance proportional to the effort applied

Question 3

What hydraulic PAS components are required in a rack and pinion?

Answer 3

• Pump and reservoir (integral PRV)
• Control Valve
• Ram cylinder

Question 4

What type of control valve is in a hydraulic PAS?

Answer 4

Spool

Question 5

What maintenance do we do for PAS?

Answer 5

• Oil level
• Leaks
• Check condition and routing of all pipes
• Check drive belt condition and tension

Question 6

if PAS is noisy, what could the problems be?

Answer 6

• Low fluid level
• Slack belt
• Malfunctioning control valve
• Internal worn pump

Question 7

If you get inadequate steering assistance what may be the problems?

Answer 7

• Low fluid level
• Slack belt
• Kinks in hoses
• Malfunctioning control valve
• Malfunctioning relief valve
• Internally worn pump
• Worn cylinder

Question 8

What may be the issues with steering judder towards locks?

Answer 8

• Low fluid level
• Slack drive belt
• Malfunctioning control valve

Question 9

What may be the issue if you get excessive steering kick back?

Answer 9

Air in the system

Question 10

What are advantages of twin steered front axle over single steer axle

Answer 10

• The static payload and stress per axle is lessened
• Road holding is improved
• Punctures don’t prevent the vehicle from being steered to a standstill

Question 11

What are the advantages of a 4 wheel steering system

Answer 11

• Superior cornering
• Improved steering responsiveness
• High speed straight line stability
• Improved lane changing
• Smaller turning radius at low speed

Question 12

What two phases of 4 wheel steering are there and what’s the difference?

Answer 12

• Same phase: Wheels turning in the same direction (high speeds)
• Opposite phase: Wheels turning in different direction (low speeds)