Wheel Alignment System: Adjustments Chevrolet Sonic I

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

1. Inspect the tires for the proper inflation and irregular tire wear.
2. Inspect the runout of the wheels and the tires.
3. Inspect the wheel bearings for backlash and excessive play. Refer to «Suspension Strut and Shock Absorber Testing - On Vehicle»(ref-542475-S10523218772013041600000) .
4. Inspect the ball joints for looseness or wear.
5. Inspect the tie rod ends for looseness or wear.
6. Inspect the control arms and stabilizer shaft for looseness or wear.
7. Inspect the steering gear for looseness at the frame.
8. Inspect the struts/shock absorbers for wear, leaks, and any noticeable noises. Refer to «Suspension Strut and Shock Absorber Testing - On Vehicle»(ref-542475-S10523218772013041600000) .
9. Inspect the steering wheel for excessive drag or poor return due to stiff or rusted linkage or suspension components.
10. 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.
4. Adjust alignment angles to vehicle specification, if necessary. Refer to «Wheel Alignment Specifications»(ref-542573-S10595292482013041600000) .

Front Camber Adjustment

1. If the front camber is out of specifications, perform the following: Remove the front strut to steering knuckle nuts (1) and the bolts (2). Replace the front strut to steering knuckle bolts (2) with the service bolts. Install the service bolts and adjust the front camber to specifications. Refer to «Wheel Alignment Specifications»(ref-542573-S10595292482013041600000) .
2. Tighten the front strut nuts (1) to 110 N.m (81 lb ft).

Wheel Alignment - Steering Wheel Angle and/or Front Toe Adjustment

1. Ensure that the steering wheel is set in a straight ahead position.
2. Loosen the tie rod jam nut (1).
3. Adjust the toe to specification by turning the inner tie rod (2). Refer to «Wheel Alignment Specifications»(ref-542573-S10595292482013041600000) .
4. Tighten the tie rod nut (1) to 60 N.m (44 lb ft).

Scheme 4

Camber is the tilting of the wheels from the vertical when viewed from the front of the vehicle. When the wheels tilt outward at the top, the camber is positive (+). When the wheel tilts inward at the top, the camber is negative (-). The amount of tilt is measured in degrees from the vertical. Camber settings influence the directional control and the tire wear.

Too much positive camber will result in premature wear on the outside of the tire and cause excessive wear on the suspension parts.

Too much negative camber will result in premature wear on the inside of the tire and cause excessive wear on the suspension parts.

Unequal side-to-side camber of 1 degree or more will cause the vehicle to pull or lead to the side with the most positive camber.

Cross Camber is the difference between the left camber value and the right camber value.

Cross Camber = L camber - R camber

Scheme 5

Caster is the tilting of the uppermost point of the steering axis either forward or backward, when viewed from the side of the vehicle. A backward tilt is positive (+) and a forward tilt is negative (-). Caster influences directional control of the steering but does not affect the tire wear . Caster is affected by the vehicle height, therefore it is important to keep the body at its designed height. Overloading the vehicle or a weak or sagging rear spring will affect caster. When the rear of the vehicle is lower than its designated trim height, the front suspension moves to a more positive caster. If the rear of the vehicle is higher than its designated trim height, the front suspension moves to a less positive caster.

With too little positive caster, steering may be touchy at high speed and wheel returnability may be diminished when coming out of a turn. If one wheel has more positive caster than the other, that wheel will pull toward the center of the vehicle. This condition will cause the vehicle to pull or lead to the side with the least amount of positive caster.

Cross Caster is the difference between the left caster value and the right caster value.

Cross caster = L caster - R caster