Checking and Adjusting the Wheel Alignment
Checking and adjusting the wheel alignment
Note! When checking and adjusting front wheel alignment the following applies:
- Any camber angle adjustment must always be made before adjusting the toe-in
- Because the rear wheels have adjustable toe-in, the front wheels must always be adjusted in relation to the car's geometric driving axis (thrust line). This is to achieve the maximum stability and minimize tire wear.
Note! All measurements must be made with the car empty. Check the tire pressure on all tires. See the specifications for the relevant tire, Tires Front Suspension.
Lift up front end
Lift under the control arms as close to the ball joints as possible.
Check for play in:
- the steering gear or tie rods
- the wheel bearings
- the upper spring strut mountings
- control arm ball joints and bushings.
If there is play in any of the above components it must be corrected. See the relevant chapters; Steering gear, replacement Steering Gear, Replacement , Front wheel bearing / hub, replacing Front Wheel Bearing/Hub, Replacement.
Set up the test equipment
Set up and calibrate test equipment according to its instructions.
Position the turntables under the front wheels. Use turntables which take up lateral movement.
Note! The car must stand level when the front wheels are on the turntables. So that the correct values are obtained when checking camber and caster.
Bounce the front suspension heavily a few times when the car has sunk onto the turntables. This must be done for the front suspension to resume the normal position.
Checking camber angle
Check the camber angle on both sides.
Correct value: 0° ± 1.0° For the C70 the following applies: -0.5° ± 1.0° .
The camber angle may vary by a maximum of 0.2°±0.7° between the left and the right wheels.
If the camber angle is outside these values, for cars from model year 1994 see Camber angle, adjusting. Camber Angle, Adjusting
Checking caster angle
Check the caster angle on both sides. Correct value: 3.35° ± 1.0° . The caster angle must not vary by more than 1.0° between the left and right sides.
Checking toe-in
Check that the instruments are adjusted in relation to each other on the front and rear axles. This is important so that the front wheel toe-in can be adjusted in relation to the car's thrust line. Thrust line is the line created when the rear wheels toe-in angles are equally divided, see illustration.
Note! The difference between the wheel symmetry line and the thrust line is called the thrust angle. This angle may deviate by a maximum of 15° from the symmetry line.
A. Wheel symmetry line
B. Thrust line
C. Thrust angle
Note! The differences in the adjacent diagram are exaggerated in order to illustrate the differences.
To set the rear wheel toe-in, see Checking and adjusting the alignment of the rear wheels Checking and Adjusting the Alignment of the Rear Wheels
Toe-in
Correct value: 0.33° ± 0.1° measured over both wheels.
Measurements are taken at the height of the hub as an angular measurement or as the difference in mm between the front and rear edges of the wheel at points A, B, or C (tread of the tire, inner shoulder and flare of the rim, respectively).
Example. The measurement at A must be 3.6 ± 1 mm greater than at a.
Adjusting toe-in
Adjustment is made using the tie rods after loosening the lock nuts. Longer rods give a greater angle and vice versa. See the table above for the correct values.
Note! The lengths of the tie rods must not vary between themselves by more than 2 mm. Measure between the lock nut and the edge of thread. Treat the tied rod threads using rustproofing agent P/N 1161432-8 after they have been tightened.
Steering wheel position
Minor deviation, adjust at the same time as the toe-in adjustment above.
For major steering wheel deviation, adjust the steering wheel position. Removal and Replacement