Wheel Alignment System: Adjustments Buick LaCrosse II facelift

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 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. Refer to «Vehicle Certification, Tire Placard, Anti-Theft, and Service Parts ID Label»(ref-621951-S40774315592014061000000) , and «Tire Diagnosis - Irregular or Premature Wear»(ref-621962-S36496921842014061000000) .
2. Inspect the runout of the wheels and the tires.
3. Inspect the wheel bearings for backlash and excessive play.
4. Inspect the ball joints and tie rod ends for looseness or wear.
5. Inspect the control arms and stabilizer shaft for looseness or wear.
6. Inspect the steering gear for looseness at the frame. Refer to «Fastener Tightening Specifications»(ref-622000-S14604278292014061000000) .
7. Inspect the struts/shock absorbers for wear, leaks, and any noticeable noises. Refer to «Suspension Strut and Shock Absorber Testing - On Vehicle»(ref-621961-S04436016482014061000000) .
8. Inspect the vehicle trim height. Refer to «Trim Height Inspection (GNB)»(ref-621961-S28979438412014061000000) , «Trim Height Inspection (GNA)»(ref-621961-S35673162342014061000000) .
9. Inspect the steering wheel for excessive drag or poor return due to stiff or rusted linkage or suspension components.

Give consideration to the condition of the equipment being used for the alignment. Follow the equipment manufacturer 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 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.
4. Adjust alignment angles to vehicle specification, if necessary. Refer to «Wheel Alignment Specifications»(ref-622003-S11479618352014061000000) .

Scheme 4

Front Camber Adjustment (GNB)

Front Camber Adjustment (GNA)

Note. The following procedure is to be performed if the front strut has to be modified en-order to adjust the front camber.

1. Position the vehicle properly on an alignment rack.
2. Remove the tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(ref-621962-S35323432082014061000000)
3. Loosen both of the front strut nuts (1) to for allow movement of the front strut.
4. Remove the lower front strut nut and bolt (2).
5. Push the front strut inward and install the front strut lower bolt (2) in the lower bolt hole of the knuckle.
6. Using a file, enlarge the inner hole (2) to the same size as the outer hole (1).
7. Remove and discard the lower bolt (3). Replace with NEW only.
8. Remove and discard the upper nut and bolt. Replace with NEW only.
9. Adjust the front camber to the proper specifications. Refer to «Wheel Alignment Specifications»(ref-622003-S11479618352014061000000) .
10. Tighten the front strut nuts. Refer to «Strut Assembly Removal and Installation (GNB)»(ref-621999-S12832328342014061000000) , «Strut Assembly Removal and Installation (GNA)»(ref-621999-S41723118182014061000000) .
11. Verify the front camber adjustment. Repeat the camber adjustment if needed.

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 (5).
3. Adjust the toe to specification by turning the adjuster (6). Refer to «Wheel Alignment Specifications»(ref-622003-S11479618352014061000000) .
4. Install the tie rod jam nut (5) and tighten to 60 (44 lb ft).

Rear Camber Adjustment (GNC)

1. Remove the and discard the rear lower control arm bolt (1). DO NOT re-use. Replace with NEW only.
2. With the NEW rear lower control arm bolt (1) in place, rotate the rear lower control arm bolt (1) until the proper camber setting is achieved. Refer to «Wheel Alignment Specifications»(ref-622003-S11479618352014061000000) .
3. Verify the rear camber specifications and adjust as necessary.
4. Tighten the rear suspension lower control arm nut (2) to 90 N.m (66 lb ft) plus 60 degrees..

Rear Camber Adjustment (GNE)

1. Remove the and discard the rear upper control arm bolt (1). DO NOT re-use. Replace with NEW only.
2. With the NEW rear upper control arm bolt (1) in place, rotate the rear upper control arm bolt (1) until the proper camber setting is achieved. Refer to «Wheel Alignment Specifications»(ref-622003-S11479618352014061000000) .
3. Verify the rear camber specifications and adjust as necessary.
4. Tighten the rear suspension upper control arm nut (2) to 150 N.m (111 lb ft).

Rear Toe Adjustment (GNC)

1. Verify the alignment on an alignment rack. Refer to «Wheel Alignment Measurement»(ref-622003-S09366874002014061000000) .
2. Remove and discard the control arm bolt (1). DO NOT re-use, replace with NEW only.
3. Install the NEW control arm bolt (1).
4. Rotate the rear suspension link inner nut (2) in order to adjust the toe angle. Refer to «Wheel Alignment Measurement»(ref-622003-S09366874002014061000000) .
5. Hand tighten the rear suspension link inner nut (2), but do not tighten the nut (2) to the specification yet.
6. Verify the rear toe angle and adjust as necessary.
7. Tighten the rear suspension link inner nut (2) to: Tighten First Pass 90 (66 lb ft) Final Pass plus 60 degrees
8. Tighten the rear suspension link outer nut to: Tighten First Pass 115 (85 lb ft) Final Pass plus 90 degrees
9. Lower the vehicle.

Rear Toe Adjustment (GNE)

1. Measure the alignment on an alignment rack. Refer to «Wheel Alignment Measurement»(ref-622003-S09366874002014061000000) .
2. If adjustment is necessary, loosen rear cam bolt and nut.
3. Rotate the cam bolt in order to adjust the toe angle. Refer to «Wheel Alignment Specifications»(ref-622003-S11479618352014061000000) .
4. Hand tighten the cam nut, but do not tighten the nut to the specification yet.
5. Re-inspect the rear toe angle and adjust as necessary.
6. Hold the cam bolt in position and tighten the nut. Tighten 150 N.m (111 lb ft)
7. Repeat the procedure for the other rear wheel.
8. Lower the vehicle.

Scheme 5

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.

1. Too much positive camber will result in premature wear on the outside of the tire and cause excessive wear on the suspension parts.
2. Too much negative camber will result in premature wear on the inside of the tire and cause excessive wear on the suspension parts.
3. 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.

Scheme 6

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.