Steering Angles and Wheel Layout — General Description (Opel Ascona C)

1. Correct alignment of the front wheels is essential for good steering performance and even tire wear. Before tackling the corners, check that the tires are properly inflated, that the front wheels are not bent, that the hub carriers are not worn, and that the steering links are in good condition with no looseness or wear in the joints.

2. Wheel placement involves four factors:

• Camber is the angle at which the wheels deviate from the vertical position when viewed from the front or rear of the vehicle. Positive camber is the angle (in degrees), which the wheels deviate outward(on top of the wheel) from the vertical position.
• Roller toe is the angle between the steering axis and a vertical line when viewed from each side of the vehicle. Roller toe-in is considered positive if the steering axle is inclined towards the rear of the vehicle with its upper end.
• Steering axle caster is the angle, viewed from the front or rear of the vehicle, between the vertical and an imaginary line drawn between the upper and lower front suspension strut mounts.
• Wheel toe is the difference in distance between the inside edge of the front wheel rims and the inside edge of the rear wheel rims. If the distance between the front inner edges is less than that between the rear ones, then the wheels are said to be positioned "toes in". If the distance between the front inner edges is greater than that between the rear ones, then the wheels are said to be positioned "toes out".

3. Since measuring small angles requires special precision instruments, it is preferable that wheel alignment and roller toe-in be checked at a service station that has the necessary equipment. Wheel alignment and toe-in are set at the time the vehicle is manufactured, and any deviation from these values must be due to accidental damage or severe wear in the suspension mountings.



4. To check the front wheel alignment, first make sure the lengths of both rods are equal when the steering is in position. in the "straight forward" position. If necessary, the rods can be adjusted in length by loosening the clamping bolts and turning the rods.

5. Purchase a measuring tool. These can be obtained in various types from auto supply stores, or such a tool can be made from a piece of steel pipe bent appropriately so as not to touch the pan, and having an adjusting screw and lock nut on one end.

6. Using such a tool, measure the distance between the inner rims of the two wheels (at the height of the hubs) behind the wheels. Push the car forward so that the wheel turns 180 degrees (half a turn) and measure the distance between the inner rims of the wheels, again at the height of the hubs, in front of the wheels. This last measurement must differ from the first by the appropriate amount of toe-in/toe-out in accordance with the Specifications. The machine must be on a level surface.

7. Where the toe-in/toe-out measurement is not correct, release the toe-in/toe-out clamp bolts and rotate the toe-in/toe-out rods one angle. Only turn them a quarter turn at a time before checking for alignment again. Do not touch the rod/ball joint threads when adjusting, use a wrench instead (see Figure 8.20). It is important not to allow the rods to become uneven in length during adjustment, which will result in incorrect steering wheel alignment and tire friction when cornering. The maximum difference in distance between the rods should not exceed 5 mm (0.2 in).





8. When finished, tighten the rod clamps without disturbing their settings. Check that the ball joint is in the center of its feed arc and that the notches in the clamps are aligned with the slots in the ball joint socket of the rod, and also that the clamp nuts are on top of the clamp clamp bolts.