Wheel Alignment Theory, Operation and Troubleshooting

General Auto Repair

GENERAL ALIGNMENT CHECKS

Before adjusting wheel alignment, check the following:

• Each axle uses tires of same construction and tread style, equal in tread wear and overall diameter. Verify that radial and axial runout is not excessive. Inflation should be at manufacturer's specifications.
• Steering linkage and suspension must not have excessive play. Check for wear in tie rod ends and ball joints. Springs must not be sagging. Control arm and strut rod bushings must not have excessive play. See Figure.
• Vehicle must be on level floor with full fuel tank, no passenger load, spare tire in place and no load in trunk. Bounce front and rear end of vehicle several times. Confirm vehicle is at normal riding height.
• Steering wheel must be centered with wheels in straight ahead position. If required, shorten one tie rod adjusting sleeve and lengthen opposite sleeve (equal amount of turns). See Figure.
• Wheel bearings should have the correct preload and lug nuts must be tightened to manufacturer's specifications. Adjust camber, caster and toe-in using this sequence. Follow instructions of the alignment equipment manufacturer.

WARNING: DO NOT attempt to correct alignment by straightening parts. Damaged parts MUST be replaced.

CAMBER

1. Camber is the tilting of the wheel, outward at either top or bottom, as viewed from front of vehicle. See Figure
2. When wheels tilts outward at the top (from centerline of vehicle), camber is positive. When wheels tilt inward at top, camber is negative. Amount of tilt is measured in degrees from vertical.

CASTER

1. Caster is tilting of front steering axis either forward or backward from vertical, as viewed from side of vehicle. See Figure.
2. When axis is tilted backward from vertical, caster is positive. This creates a trailing action on front wheels. When axis is tilted forward, caster is negative, causing a leading action on front wheels.

TOE-IN ADJUSTMENT

Toe-in is the width measured at the rear of the tires subtracted by the width measured at the front of the tires at about spindle height. A positive figure would indicate toe-in and a negative figure would indicate toe-out. If the distance between the front and rear of the tires is the same, toe measurement would be zero. To adjust:

1) Measure toe-in with front wheels in straight ahead position and steering wheel centered. To adjust toe-in, loosen clamps and turn adjusting sleeve or adjustable end on right and left tie rods. See Figure 1 and Figure 2

2) Turn equally and in opposite directions to maintain steering wheel in centered position. Face of tie rod end must be parallel with machined surface of steering rod end to prevent binding.

3) When tightening clamps, make certain that clamp bolts are positioned so there will be no interference with other parts throughout the entire travel of linkage.

TOE-OUT ON TURNS

1. Toe-out on turns (turning radius) is a check for bent or damaged parts, and not a service adjustment. With caster, camber, and toe-in properly adjusted, check toe-out with weight of vehicle on wheels.
2. Use a full floating turntable under each wheel, repeating test with each wheel positioned for right and left turns. Incorrect toe-out generally indicates a bent steering arm. Replace arm, if necessary, and recheck wheel alignment.

STEERING AXIS INCLINATION

1. Steering axis inclination is a check for bent or damaged parts, and not a service adjustment. Vehicle must be level and camber should be properly adjusted. See Figure
2. If camber cannot be brought within limits and steering axis inclination is correct, steering knuckle is bent. If camber and steering axis inclination are both incorrect by approximately the same amount, the upper and lower control arms are bent.

Alignment Troubleshooting

Premature Tire Wear

• Improper tire inflation: Check tire pressure
• Front alignment out of tolerance
• Suspension components worn
• Steering system components worn
• Improper standing height
• Uneven or sagging springs
• Bent wheel
• Improper torsion bar adjustment
• Loose or worn wheel bearings
• Worn or defective shock: Replace shock absorbers
• Tires out of balance: Check tire balance

Pulls to One Side

• Improper tire inflation: Check tire pressure
• Brake dragging
• Mismatched tires
• Broken or sagging spring
• Broken torsion bar
• Power steering valve not centered
• Front alignment out of tolerance
• Defective wheel bearing
• Uneven sway bar links
• Frame bent
• Steering system bushing worn

Hard Steering

• Idler arm bushing too tight
• Ball joint tight or seized
• Steering linkage too tight
• Power steering fluid low: Add proper amount of fluid
• Power steering drive belt loose
• Power steering pump defective
• Steering gear out of adjustment
• Incorrect wheel alignment
• Damaged steering gear
• Damaged suspension
• Bent steering knuckle or supports

Vehicle "Wanders

• Strut rod or control arm bushing worn
• Loose or worn wheel bearings
• Improper tire inflation: Check tire pressure
• Stabilizer bar missing or defective
• Wheel alignment out of tolerance
• Broken spring
• Defective shock absorber: Replace shock absorbers
• Worn steering & suspension

Front End Shimmy

• Tire out of balance/round: Check tire balance
• Excessive wheel runout
• Insufficient or improper caster
• Worn suspension or steering components
• Defective shock absorbers: Replace shock absorber
• Wheel bearings worn or loose
• Power steering reaction Bracket loose
• Steering gear box (rack) mounting loose
• Steering gear adjustment loose
• Worn spherical joints

Toe-In Not Adjustable

• Lower control arm bent
• Frame bent: Check frame for damage

Camber Not Adjustable

• Control arm bent
• Frame bent: Check frame for damage
• Hub and bearing not seated properly

FYI: It is recommended that you have a reputable automotive service shop handle the wheel alignment process. This may save you time and headaches down the road. Most auto shops may have wheel alignment specials so check with your local shop.


General Auto Repair

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