SuspensionWheel Alignment Measurement
Wheel Alignment Measurement
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/pull is defined as follows: At a constant
highway speed on a typical straight road, lead/pull is the amount
of effort required at the steering wheel to maintain the vehicle's
straight path. Lead is the vehicle deviation from a straight path
on a level road without pressure on the steering wheel.
Before performing any adjustment affecting wheel alignment,
perform the following inspections and adjustments in order to
ensure correct alignment readings:
| • |
Inspect the tires for the
proper inflation and irregular tire wear. |
| • |
Inspect the runout of the
wheels and the tires. |
| • |
Inspect the ball joints for
looseness or wear. |
| • |
Inspect the tie rod ends for
looseness or wear. |
| • |
Inspect the control arms and
stabilizer shaft for looseness or wear. |
| • |
Inspect the steering gear for
looseness at the frame. |
| • |
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:
| 1. |
Install the alignment
equipment according to the manufacturer's instructions.
|
| 2. |
Jounce the front and the rear
bumpers 3 times prior to checking the wheel alignment. |
| 3. |
Measure the alignment angles
and record the readings. |
|
Note:
| • |
Record the
"Before" and "After" alignment measurements. |
| • |
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. |
|
|
|
18 Steering & suspension
