Pinpoint Tests

Suspension System

Pinpoint Tests


Pinpoint Test A: Vehicle Drifts/Pulls

This pinpoint test is intended to diagnose the following:
- Unevenly loaded vehicle
- Tire pressure
- Tire forces
- Brake drag
- Incorrect vehicle alignment
- Steering system


PINPOINT TEST A: VEHICLE DRIFTS/PULLS

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A1 CHECK FOR UNEVENLY LOADED VEHICLE


- Visually check the vehicle for an uneven loading condition.
- Is the vehicle unevenly loaded?

Yes
ADVISE the customer of uneven loading condition.

No
GO to A2.

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A2 CHECK THE TIRE PRESSURE


- Check the tire pressures. Refer to the Vehicle Certification (VC) label located on the driver door jamb.
- Is the tire pressure OK?

Yes
GO to A3.

No
ADJUST the tire pressures to the specified pressure.

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A3 ISOLATE TIRE PULL CONDITION


- Cross the front wheel and tire assemblies from left-to-right.
- Does the vehicle pull/drift?

Yes
If the vehicle drifts/pulls in the opposite direction, tire forces are causing the drift/pull. REFER to Wheels and Tires Testing and Inspection to diagnose tire drift/pull. If the vehicle drifts/pulls in the same direction, GO to A4.

No
Tire forces were causing the drift/pull and the concern has been corrected.

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A4 CHECK FOR BRAKE DRAG


- Spin all 4 wheel and tire assemblies by hand and check for brake drag.
- Do the wheels spin freely?

Yes
GO to A5.

No
REFER to Brake System - General Information Symptom Related Diagnostic Procedures to diagnose brake drag condition.

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A5 CHECK FOR STEERING SYSTEM DRIFT/PULL


- Check the steering system components. Refer to Steering System Initial Inspection and Diagnostic Overview to diagnose steering system drift/pull/wander condition.
- Is the steering system the cause of the drift/pull?

Yes
REPAIR the steering system as necessary.

No
GO to A6.

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A6 CHECK THE WHEEL ALIGNMENT


- NOTE: A one-quarter degree to one-half degree side-to-side caster difference is usually sufficient to correct a drift/pull concern.

- Using alignment equipment and the manufacturers instructions, check the wheel alignment.
- Is the caster total/split and the camber total/split within specification?

Yes
ADJUST the caster total/split to counteract the drift/pull concern. REFER to General Procedures.

If the concern is vehicle drifts/pulls left, INCREASE the caster total/split towards the upper and of the specification range.

If the concern is vehicle drifts/pulls right, DECREASE the caster total/split towards the lower end of the specification range.

No
ADJUST the camber and caster total/split as close to the nominal specification as possible. REFER to General Procedures.

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