Steering and vibration complaints are not always the result
of improper alignment. One possible cause is wheel and tire imbalance. Another
possibility is tire lead due to worn or improperly manufactured tires.
Lead is the vehicle deviation from a straight path on a level road without
pressure on the steering wheel. Refer to
Radial Tire Lead/Pull Correction
in Tires and Wheels in order
to determine if the vehicle has a tire lead problem.
Before performing any adjustment affecting wheel alignment, perform
the following inspections and adjustments in order to ensure correct alignment
readings:
| • | Inspect the wheel bearings for backlash and excessive play. Refer
to
Wheel Bearings Diagnosis
in
Suspension General Diagnosis. |
| • | Inspect the ball joints and tie rod ends for looseness or wear. |
| • | Inspect the control arms and stabilizer shaft for looseness or
wear. |
| • | Inspect the steering wheel for excessive drag or poor return due
to stiff or rusted linkage or suspension components. |
| • | Inspect the fuel level. The fuel tank should be full or the vehicle
should have a compensating load added. |
Give consideration to excess loads, such as tool boxes, sample cases,
etc. If normally carried in the vehicle, these items should remain in the
vehicle during alignment adjustments. Give consideration also to the
condition of the equipment being used for the alignment. Follow the equipment
manufacturer's instructions.
Satisfactory vehicle operation may occur over a wide range
of alignment settings. However, if the setting exceeds the service allowable
specifications, correct the alignment to the service preferred specifications.
Refer to
Wheel Alignment Specifications
.
Perform the following steps in order to measure the front and rear alignment
angles:
- Install the alignment equipment according to the manufacturer's
instructions.
- Jounce the front and the rear bumpers 3 times prior to
checking the wheel alignment.
- Measure the alignment angles and record the readings.
Important: When performing adjustments to vehicles requiring a 4-wheel alignment,
set the rear wheel alignment angles first in order to obtain proper front
alignment angles.
- Adjust alignment angles to vehicle specification, if necessary. Refer
to
Wheel Alignment Specifications
.
