Wheel Alignment Specifications & Adjustment Procedures: Adjustments Chevrolet Silverado 2500

Learn Wheel Alignment

After replacement of the handwheel position sensor, rear wheel position sensor or rear wheel steering control module it is necessary to perform the learn wheel alignment procedure.

Alignment Procedure

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 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

1. Inspect the tires for the proper inflation. Inspect tires for irregular tire wear. Refer to «TIRE DIAGNOSIS - IRREGULAR OR PREMATURE WEAR»(ref-175630-S17267390332005042500000) .
2. Inspect the runout of the wheels and the tires.
3. Inspect the wheel bearings for backlash and excessive play. Refer to «WHEEL BEARINGS DIAGNOSIS (SEALED)»(ref-175636-S08410193362005042500000) .
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-175031-S35875189182005041400000) .
7. Inspect the struts/shock absorbers for wear, leaks, and any noticeable noises. Refer to «STRUTS OR SHOCK ABSORBERS ON-VEHICLE TESTING»(ref-175636-S18640932982005042500000) .
8. Inspect the vehicle trim height. Refer to «TRIM HEIGHT INSPECTION PROCEDURE»(ref-175636-S21676013112005042500000) .
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. 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.
4. Adjust alignment angles to vehicle specification, if necessary. Refer to «Wheel Alignment Specifications»(ref-175627-S41062928602005042500000) , then perform the learn alignment procedure.

Learn Wheel Alignment Procedure

1. Turn ignition to ON position, with the engine ON.
2. Install the scan tool.
3. Center the steering wheel.
4. Lift the rear of the vehicle off the ground ensuring the rear wheels are centered.
5. Go to the Learn Alignment menu choice in the scan tool. Follow the prompts on the scan tool. Important: When prompted by the scan tool you must turn the steering wheel a full 90° to the left and a full 90° to the right and then to center and hold. If this step is not done properly then it is possible to cause a false DTC for the steering wheel position sensor.
6. Press the continue button.
7. Use the scan tool to clear all rear wheel steering DTC's.

Measuring Wheel Alignment (Without Rear Wheel Steering)

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 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

1. Inspect the tires for the proper inflation and irregular tire wear. Refer to «TIRE DIAGNOSIS - IRREGULAR OR PREMATURE WEAR»(ref-175630-S17267390332005042500000) .
2. Inspect the runout of the wheels and the tires.
3. Inspect the wheel bearings for backlash and excessive play. Refer to «WHEEL BEARINGS DIAGNOSIS (SEALED)»(ref-175636-S08410193362005042500000) .
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-175031-S35875189182005041400000) .
7. Inspect the struts/shock absorbers for wear, leaks, and any noticeable noises. Refer to «STRUTS OR SHOCK ABSORBERS ON-VEHICLE TESTING»(ref-175636-S18640932982005042500000) .
8. Inspect the vehicle trim height. Refer to «TRIM HEIGHT INSPECTION PROCEDURE»(ref-175636-S21676013112005042500000) .
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. 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.
4. Adjust alignment angles to vehicle specification, if necessary. Refer to «Wheel Alignment Specifications»(ref-175627-S41062928602005042500000) .

Scheme 13

Scheme 14

Scheme 15

Scheme 16

Scheme 17

1. Determine if the vehicle is relative to frame or relative to ground. If caster is relative to frame, the caster values must be compensated for the measured frame angle. To determine the frame angle use a digital protractor or equivalent.
2. Frame angle is positive when higher in the rear. Measure both sides of the frame and take an average from those measurements. Then add the average frame angle to the caster reading obtained in step 5 of this procedure when making adjustments.
3. Frame angle is negative when lower in the rear. Measure both sides of the frame and take an average from the measurements. Then subtract the average frame angle from the caster reading obtained in step 5 of this procedure when making adjustments.
4. The caster and camber adjustments are made by rotating the offset cam bolt and the cam in the slotted frame bracket in order to reposition the control arm. Important: Before adjusting the caster and camber angles, jounce the front bumper three times to allow the vehicle to return to normal height. Measure and adjust the caster and the camber with the vehicle at curb height. The front suspension Z dimension is indicated in Trim Heights. Refer to «TRIM HEIGHT INSPECTION PROCEDURE»(ref-175636-S21676013112005042500000) .
5. For an accurate reading, do not push or pull on the tires during the alignment process.
6. Determine the caster angle (2). Be sure to compensate for frame angle where required.
7. Determine the positive camber (2) or negative camber (3) angle.
8. Remove the pinned adjusting cam insert. Do not reinstall the cam insert.
9. Loosen the upper control arm cam adjustment bolts.
10. Adjust the caster and the camber angle by turning the cam bolts until the specifications have been met. When the adjustments are complete, hold the cam bolt head in order to ensure the cam bolt position does not change while tightening the nut. Tighten the cam nuts to 190 N.m (140 ft lbs).
11. Verify that the caster and the camber are still within specifications. Refer to . «Wheel Alignment Specifications»(ref-175627-S41062928602005042500000) . When the caster and camber are within specifications, adjust the toe. Refer to «Front Toe Adjustment»(ref-175627-S24646467182005042500000) .

Front Toe Adjustment

1. Loosen the jam nut on the tie rod (2).
2. Rotate the inner tie rod (1) to the required toe specification setting. Refer to «Wheel Alignment Specifications»(ref-175627-S41062928602005042500000) .
3. Tighten the jam nut on the tie rod. Tighten the tie rod jam to 68 N.m (50 ft lbs).
4. Check the toe setting after tightening.
5. Re-adjust the toe setting if necessary.

Rear Toe Adjustment

1. Loosen the jam nut on the tie rod (1).
2. Rotate the inner tie rod to the required toe specification setting. Refer to «Wheel Alignment Specifications»(ref-175627-S41062928602005042500000) .
3. Tighten the jam nut on the tie rod. Tighten the tie rod jam to 65 N.m (48 ft lbs).
4. Check the toe setting after tightening.
5. Re-adjust the toe setting if necessary.

Scheme 18

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 and is not adjustable on this vehicle. 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.

Scheme 19

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.

Scheme 20

Toe is a measurement of how much the front and/or rear wheels are turned in or out from a straight-ahead position. When the wheels are turned in, toe is positive (+). When the wheels are turned out, toe is negative (-). The actual amount of toe is normally only a fraction of a degree. The purpose of toe is to ensure that the wheels roll parallel.

Toe also offsets the small deflections of the wheel support system that occur when the vehicle is rolling forward. In other words, with the vehicle standing still and the wheels set with toe-in, the wheels tend to roll parallel on the road when the vehicle is moving.

Improper toe adjustment will cause premature tire wear and cause steering instability.