A front wheel or four wheel alignment is a beneficial service to perform on your vehicle during recommended maintenance schedule intervals. Alignments measure many angles of the vehicle's wheels and suspension components. Their main purpose is correct the thrust angle of the vehicle. Alignments are measured in degrees (usually by a computer with sensors attached to the wheels) and there are three common denominators to consider when performing a front wheel alignment; caster (the steering angle of the wheel attached to the suspension), camber (the vertical angle of the wheel), and toe (the difference in measurement from the front of the wheel to the back of the wheel). Only adjustments made in these categories will correct them (or replacement of damaged parts). Caster is unadjustable in most front wheel drive vehicles and often indicates a damaged suspension component.
Test drive the vehicle. An alignment should always start and end with a test drive. This way you will know what symptoms to look for while performing the alignment. Examples of some problems: the steering wheel is off-centre, the vehicle is pulling in one direction, and there are vibrations when driving, to name a few.
Enter the vehicle's year, make, model, and design into the alignment machine computer to display the ideal alignment specifications. This will be compared to the actual vehicle's measurements to compensate and correct them.
Lift the vehicle on the alignment rack to a comfortable height and level, and lock the rack. Lift the vehicle by the centre jacks of the alignment rack to suspend the wheels. Check the tires for uneven wear. Check the front end and rear axle for any compromised suspension or steering components. If the vehicle has a bad ball joint, tie rod end, broken coil spring, loose wheel bearing, or any other problem with the suspension or steering, the component needs to be replaced before the alignment is performed.
Check and adjust tire pressure to the specifications of the vehicle.
Remove the hub caps if applicable.
Install the alignment heads to each wheel. Most alignment machines require the alignment heads be attached to all four wheels, even if no adjustments are made to the rear. Many front wheel drive vehicles have adjustments that can be performed to the rear, and if it is available, it should be performed before the front wheel alignment adjustments are made.
Perform the wheel run-out compensation for each wheel and head (if applicable). This turns the wheel back and forth and measures the alignment angles of each wheel.
Apply the brake lock bar between the front seat and the brake pedal and then lower the vehicle from the centre jacks onto the alignment rack and jounce the suspension. If applicable, remove the turntable locks for the front wheels before lowering the front axle onto them. Jounce both the front and rear suspension to settle the suspension components.
Lock and level the alignment heads.
Perform the caster swing on the front wheels per following the instructions of the alignment machine computer. Caster is the measurement of the wheel pivoting, as it is attached to the suspension when it is turning, therefore, it is only measured in the front steering axle.
Start the car and turn the steering wheel back and forth to settle the steering components. Straighten the steering wheel and lock it with the steering wheel lock.
Prompt the alignment machine computer to display the vehicle's current specifications. Compare these to the ideal specifications to determine what needs to be adjusted to correct the alignment. As mentioned, if the rear alignment is out and needs to be adjusted, this has to be performed first. Most alignment machines with current specs will tell you what can or cannot be adjusted to the specific vehicle you're aligning. This will help you locate the components and make the required adjustments to them.
Correct caster and camber adjustments first on front wheel alignments. In vehicles that have caster adjustments available, most times they are incorporated with the camber adjustment. Many front wheel drive vehicles do not offer caster adjustments, but correcting the camber may bring the caster within specs. Camber is often corrected by loosening the strut bolts and repositioning the wheel manually and then re-tightening the strut bolts while holding the wheel in the new position. Refer to the alignment machine instructions (or a repair manual) for the specific vehicle to perform the correct caster and camber adjustments.
Adjust the toe after the caster and camber adjustments have been made. Toe is most often adjusted by loosening the jam nut of the outer tie rod end and then turning the inner tie rod end arm. Once the toe is withing designated specifications, you would hold the inner tie rod end stationary while re-tightening the jam nut to lock the position into place.
Restart the car, remove the steering wheel lock, turn the steering wheel back and for a couple times, then recenter and replace the steering wheel lock. Recheck the current alignment specifications on the alignment machine. Sometimes, it is not uncommon to have to readjust toe measurement after settling the steering components. Get out of the vehicle and step off of the alignment rack before checking the specs; your weight in the vehicle and on the rack can manipulate the specs.
Remove the heads and lower the vehicle when you're done.
Test drive the vehicle to ensure the symptoms it had before are gone or can be explained (like cupped tires vibrating) that the alignment service will not immediately correct.