STEERING SYSTEM DIAGNOSIS/TESTING

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Inspection/Verification

Caution
• Do not hold the steering wheel fully turned to the left or right for 3-5 s or more. Damage to the power steering pump can result.
Note
• Make the following preliminary checks before repairing the steering system.

1. Verify the customer concern by operating the steering system.

2. Tire inspection

• Check the tire pressure.
• Verify that all tires are sized to specification. (See SUSPENSION TECHNICAL DATA.)
• Check the tires for damage or uneven wear. (See WHEEL AND TIRES DIAGNOSIS/TESTING.)

3. Belt and tensioner inspection

• Refer to Section 01-10 for diagnosis and testing of the accessory drive system.

4. Fluid level inspection

• Verify that the power steering fluid level is within the appropriate hot or cold range on the dipstick. Add M-III or equivalent (e.g. Dexron®II).

5. Air bleeding

• Verify that there is no air in the power steering system. Run the engine until it reaches normal operating temperature. Turn the steering wheel to the left and right several times without hitting the stop positions.

6. Steering force inspection

• Refer to the "Component Tests."

7. Visually inspect for obvious signs of mechanical damage. Refer to the following chart.

Mechanical malfunction

• Loose tie-rod ends
• Loose suspension structural components
• Loose steering shaft universal joints
• Loose steering shaft bolts
• Steering gear
• Binding or misaligned steering column
• Power steering oil pump
• Bent or pinched power steering hoses

8. If an obvious cause for an observed or reported malfunction is found, if possible correct the cause before proceeding to the next step.

9. If the malfunction is not visually evident, determine the symptom and proceed to the following symptom chart.

Steering System Symptom Definitions

Drift/Pull

• Pull is a tugging sensation, felt by the hands on the steering wheel, that must be overcome to keep the vehicle going straight.
• Drift describes what a vehicle with this condition does with hands off the steering wheel.
• Vehicle-related drift/pull, on a flat road, can cause a consistent deviation from the straight-ahead path and requires constant steering input in the opposite direction to counteract the effect.
• Drift/pull can be induced by conditions external to the vehicle (i.e., wind, road camber).

Excessive steering wheel play

• Excessive steering wheel play is a condition in which there is too much steering wheel movement before the wheels move. A small amount of steering wheel free play is considered normal.

Feedback

• Feedback is a roughness felt in the steering wheel when the vehicle is driven over rough pavement.

Hard steering or lack of assist

• Hard steering or lack of assist is experienced when the steering wheel effort exceeds specifications. Hard steering can remain constant through the full turn or occur near the end of a turn. It is important to know the difference between hard steering/lack of assist and binding.
• Hard steering or lack of assist can result from either hydraulic or mechanical conditions. It is extremely important to know if this concern occurs during driving, or while the vehicle is stopped.

Nibble

• Sometimes confused with shimmy, nibble is a condition resulting from tire interaction with various road surfaces and is observed by the driver as small rotational oscillations of the steering wheel.

Poor returnability/sticky steering

• Poor returnability and sticky steering is used to describe poor return to center of the steering wheel after a turn or a steering correction is completed.

Shimmy

• Shimmy, as observed by the driver, is large, consistent, rotational oscillations of the steering wheel resulting from large, side-to-side (lateral) tire/wheel movements.
• Shimmy is usually experienced near 64 km/h {40 mph}, and can begin or be amplified when the tire contacts pot holes or irregularities in the road surface.

Wander

• Wander is the tendency of the vehicle to require frequent, random left and right steering wheel corrections to maintain a straight path down a level road.

Symptom Chart

Condition

Possible Cause

ACTION

• Hard steering or lack of assist
• Seized steering shaft universal joints.
• Damaged, fractured steering column bearing(s).
• Power steering oil pump
• Inspect the power steering fluid.
• Suspension structural components.
• Refer to Section 02-10 for suspension system diagnosis/testing.
• Steering gear internal leakage.
• Inspect the power steering fluid.
• Excessive steering pump noise
• Power steering oil pump
• Inspect the power steering fluid.
• Excessive steering wheel play
• Damaged, loose, or worn tie-rod end.
• Go to the "Component Tests, Steering linkage".
• Loose, worn or damaged tie rod.
• Inspect the tie rod. (See STEERING GEAR AND LINKAGE INSPECTION.)
• Damaged/worn steering gear.
• Loose, worn or damaged steering column bearing(s).
• Loose, worn or damaged steering shaft universal joint(s).
• Wander
• Unevenly loaded or overloaded vehicle.
• Inform the customer of incorrect vehicle loading.
• Loose, worn or damaged tie rod.
• Inspect the tie rod. (See STEERING GEAR AND LINKAGE INSPECTION.)
• Loose, worn or damaged tie-rod ends.
• Go to the "Component Tests, Steering linkage."
• Loose or worn lower steering gear mounting bolts.
• Loose steering shaft universal joint.
• Loose, worn or damaged steering shaft universal joints.
• Worn or damaged steering column bearing(s).
• Suspension structural component
• Refer to section 02-10 for suspension system diagnosis/testing.
• Drift/Pull
• Unevenly loaded or overloaded vehicle.
• Inform the customer of incorrect vehicle loading.
• Wheel Alignment
• Adjust if necessary. Refer to section 02-11.
• Loose, worn or damaged tie rod.
• Inspect the tie rod. (See STEERING GEAR AND LINKAGE INSPECTION.)
• Loose, worn or damaged tie-rod ends.
• Go to the "Component Tests, Steering linkage."
• Suspension structural components
• Refer to section 02-10 for suspension system diagnosis/testing.
• The steering gear valve effort is out of balance.
• Go to "Component Tests, Steering gear valve" in this section.
• Check the brake system for correct operation.
• Refer to section 04-10.
• Incorrect frame/underbody alignment.
• Correct if necessary. Refer to Body Shop Manual.
• Feedback
• Loose, worn or damaged tie rod.
• Inspect the tie rod. (See STEERING GEAR AND LINKAGE INSPECTION.)
• Loose, worn or damaged tie-rod ends.
• Go to the "Component Tests, Steering linkage."
• Loose or damaged steering gear insulators or bolts.
• Install new bolts or tighten the retaining bolts. Refer to section 211-02.
• Loose steering gear mounting bolts.
• Loose suspension bushings, fasteners or ball joints.
• Replace with a new component if necessary. Refer to section 02-10.
• Worn or damaged steering column bearing(s).
• Poor returnability/sticky steering
• Binding steering shaft universal joints.
• Loose, worn or damaged tie-rod ends.
• Go to the "Component Tests, Steering linkage."
• Suspension structural components
• Refer to section 204-00 for suspension system diagnosis/testing.
• Binding steering column bearing(s).
• Shimmy
• Loose, worn or damaged tie-rod end.
• Go to the "Component Test, Steering linkage."
• Loose, worn or damaged tie rod.
• Inspect for the tie rod articulation torque. (See STEERING GEAR AND LINKAGE INSPECTION.)
• Suspension structural components
• Refer to section 02-10 for suspension system diagnosis/testing.

Component Tests

Steering linkage

Note
• Excessive vertical motion of the studs for the relative to the sockets can indicate excessive wear.

1. With the parking brake applied, perform the following.

(1) Have an assistant rotate the steering wheel back and forth 360 degrees and watch for relative motion of the studs in the steering linkage ball sockets.
(2) Look for a loose steering gear mounting.

Steering gear valve

1. With the vehicle in motion, place the transmission in Neutral and turn the engine off.

• If the vehicle does not pull with the engine off, repair or install a new steering gear. (See STEERING GEAR AND LINKAGE REMOVAL/INSTALLATION (L.H.D.).)(See STEERING GEAR AND LINKAGE REMOVAL/INSTALLATION [YF (2.0 L Zetec), AJ (3.0 L Duratec)](R.H.D.).)(See STEERING GEAR AND LINKAGE REMOVAL/INSTALLATION [L3](R.H.D.).)

2. If the vehicle pulls with the engine off, leakage is occurring. Cross-rotate the front wheels.

3. If the vehicle pulls to the opposite side, cross-rotate the front and rear wheels on the same side.

4. If the vehicle pull direction does not change, check the front suspension structural components, wheel alignment and frame alignment.