General information
Vehicle wheel alignment
A - B = C (Camber angle in degrees)
D = Angle of longitudinal inclination of the axis of rotation of the wheel (run-out) in degrees
E - F = Tolerance in millimeters
G = Toe in degrees
1. The angles of the front wheels determine the geometry of the position of the latter relative to the suspension of the car and the road surface. Violation of the adjustment of this geometry leads to a decrease in the controllability of the car and an increase in the rate of tire wear. The number of angles of installation of the front wheels of the car to be controlled includes camber, run-out (the angle of the longitudinal inclination of the axis of rotation of the wheel) and convergence (refer to illustration above).
2. Adjusting the geometry of the front suspension requires the use of special expensive and bulky equipment and should be entrusted to car service specialists.
3. Convergence is the amount of convergence to each other of the front edges of the wheels of the car. Such a violation of the parallelism of the wheels allows minimizing tread wear due to skidding when making turns. At zero convergence, the distance between the front edges of the wheels is equal to the distance between their rear edges. Normal convergence is usually less than a fraction of an inch (1 inch = 2.54 cm). Adjustment of the convergence of the front wheels is carried out by adjusting the length of the steering rods by changing the position of their tips. Violation of the adjustment of convergence leads to accelerated wear of the tire tread due to their slippage on the road surface.
4. Camber is the angle of inclination of the plane of the wheels relative to the vertical. If the wheels are tilted with their upper edges outward, the camber is called positive, and vice versa. Camber is measured in degrees. The correct camber adjustment determines the size and position of the tread contact patch with the road and allows you to compensate for changes in suspension geometry during cornering and when driving on uneven road surfaces. Camber adjustment is made by rotating special adjusting cams installed in the front and rear of the upper suspension arms.
5. Coasting is the angle of longitudinal inclination of the axis of rotation of the wheel, i.e., the angle of deviation from the vertical of the axis of rotation of the wheel in the plane of the latter. If the axis of rotation is tilted back, the coast is called positive, and vice versa. The runout adjustment is made simultaneously with the camber adjustment. By analogy, the transverse angle of inclination of the axis of rotation of the wheel is the angle of deviation of an imaginary kingpin from the vertical in a plane perpendicular to the DP of the car.
Checking and adjusting wheel alignment
1. Assess the degree of tread wear, check tire inflation pressure.
2. Make sure that the amount of lateral runout of the wheels does not exceed 1.2 mm.
3. Check the front wheel bearing preload adjustment.
4. Estimate reliability of fastening of components of a forward suspension bracket and a steering drive. Estimate the backlash of the ball bearings.
5. Check up serviceability of a condition of shock-absorbers.
Checking and adjusting the camber and angles of the longitudinal and transverse inclinations of the axis of rotation of the wheel
1. Drive the car onto the adjusting stand and measure the parameters under control listed in the heading of the subsection (see Specifications).
2a. If the camber and/or caster angle is (coastdown) does not comply with accepted standards, an appropriate adjustment should be made by rotating the front...
2b....and/or the rear adjusting cam of the lower control arm (refer to accompanying illustrations).
3. If, after performing the camber and runout adjustment, the lateral inclination of the steering axis of the wheel is outside the permissible range, the condition of the steering knuckle and front suspension elements should be checked.
Checking and adjusting the convergence of the front wheels
1. Rock the car to shrink the suspension elements.
2. Straighten the front wheels and roll the vehicle forward approximately 5 meters.
3. Mark the center points of the back sides of the protectors and measure the distance between them (IN) (refer to accompanying illustration).
4. Roll the car forward so that the marked marks move to the height of the wheel axle, but from the front side of the latter and make a measurement similar to the previous one (A) (refer to accompanying illustration).
5. The convergence value is determined by subtracting from the result of the first measurement the result of the second (B-A). Compare the resulting difference with the requirements Specifications.
6. If necessary, loosen the nuts of the tie rod ends of the steering rods and adjust the length of the latter accordingly. Make sure that after completing the adjustment, the lengths of the rods remain equal to each other.