15:23. Adjustment of angles of installation of wheels - the general information

Definitions

The geometry of the steering mechanism and suspension bracket is defined by four key parameters - all corners are expressed in degrees (convergence installation is also expressed in sizes); corners of inclinations of an axis of turn of a wheel are counted from the imagined line drawn on an axis of a rack of the suspension bracket prolonged, if necessary, up to a common ground with the earth.


Disorder is a corner on which the plane of a wheel is rejected from a vertical. Disorder is considered positive when the top part of wheels is inclined outside from a vertical; disorder is called negative when the top part of wheels is inclined from a vertical inside.

Disorder of wheels is not subject to adjustment and is given only for reference; measurement of disorder of wheels can be performed by means of the special measuring instrument. In case of detection of noticeable deviations from the required values of a corner of disorder of wheels, the car has to be subjected to careful professional check as malfunction can be caused only by wear or damage of elements of a body or components of a suspension bracket.

The corner of a longitudinal inclination of an axis of turn of a wheel is a corner between the axis and a vertical passing through a tire contact point in the longitudinal plane of the car. The corner of a longitudinal inclination is considered positive when the axis is inclined so that its continuation is crossed with the earth ahead from a wheel contact point. The inclination of an axis is considered negative when the line is crossed with the earth behind a point of a contact with an earth wheel.

The longitudinal inclination of an axis of turn of a wheel is not subject to adjustment and is given here as it can be checked by means of the special measuring instrument. If the measured size considerably differs from the required values, the car is subject to careful professional check since wear or damage of elements of a body or components of a suspension bracket can be a cause of defect.

The corner of a cross inclination of an axis of turn of a wheel (SAI) known also under the name of a corner of a cross inclination шкворня (KPI), is a corner between the axis of turn and a vertical passing through a tire contact point in the cross plane of the car.

SAI/KPI is not subject to adjustment and is given only for reference.

The convergence - is a corner between an axis of diametrical section of a wheel and a longitudinal axis of the car at the top view.

The convergence is called positive when wheels are turned to each other forward on the car whereas the negative convergence (divergence) is carried out at a turn of wheels outside, looking on the car forward.


Adjustment of a convergence of forward wheels is carried out by a navinchivaniye or a vyvinchivaniye of tips of steering drafts that leads to change of length of assemblies of steering drafts.

The convergence of back wheels is not subject to adjustment and is given only for reference. However it can be measured and in case of detection of noticeable difference from the required values the car has to be driven away in a workshop for professional survey as only wear and damage of elements of a body or components of a suspension bracket can be a cause of defect.

Check - general information

As conducting check of correctness of angles of installation of wheels requires use of the special measuring equipment and certain skills, it is better to provide conducting check and adjustment to representatives of SAAB or experts of a workshop of car service. It is necessary to notice that now, the corresponding equipment the majority of tire workshops has.

For exact check the car has to be unloaded, with a tank the filled fuel, and besides to have the correct road gleam (address the Section Removal and installation to the place of back screw springs).

Before starting check, make sure that the tires conforming to requirements of Specifications are installed on the car, check pressure in tires, define wear of a protector, a beating of wheels, a condition of bearings of naves, a side play of a steering wheel, and also a condition of components of a forward suspension bracket (The head Routine maintenance). Make necessary corrections.

Park the car on the flat platform, make sure that forward wheels are in situation directly forward, then, for shrinkage of a suspension bracket, shake the car in front and behind. Release the emergency brake if it is cocked, and roll away the car back, approximately on 1 m, then again forward - it is necessary for removal of tension in components of the steering mechanism and a suspension bracket.

Check and adjustment of a convergence of wheels

Convergence of forward wheels

The convergence of forward wheels is defined by measurement of distance between lobbies and rear inner edges of rims of wheels. Patent tools for measurement of a convergence are available shops of automobile accessories.

Make the preparation of the car described in the Sections Removal and installation to the place of the lower lever of a back suspension bracket, Removal and installation to the place of a tube of a back axis.

Now it is necessary to prepare the device for measurement of distance between wheels. There are two types of measuring instruments, each of which can be acquired in shops of automobile accessories. The first device is intended for measurement of distance between lobbies and rear inner edges of wheels as it is described above, at the motionless car. The second measuring instrument known under the name "scuff plate" is intended for measurement of the current provision of contact surfaces of tires in relation to the surface of the road, on the moving car. Measurement is performed by a nakatyvaniye or arrival by the car on a plate which slightly moves, leaving on itself a mark from the tire; the movement is fixed on a scale. Each type of the measuring instrument has the advantages and shortcomings, however both can be used for obtaining satisfactory result, on condition of the correct and their frequent use. Alternatively, the tool for measurement of distance between wheels can be manufactured of the piece of a steel pipe bent so that not to adjoin to the engine and the transmission, on one end of a pipe there has to be an adjusting screw and a lock-nut.

The convergence of wheels can be also measured in the majority of tire workshops.

 PERFORMANCE ORDER

1. When carrying out measurements you watch that wheels were in situation directly forward.
2. In case of need carrying out adjustment, clear tips of steering drafts around lock-nuts of adjusting fingers.
3. Weaken lock-nuts (on one on the external and internal ends of each adjusting finger) and by means of couple of clips, turn each steering draft on the identical number of turns in the same direction. For once turn each draft on a quarter of a turn. Then, you perform measurement again.
4. Make sure that spherical hinges of tips of steering drafts of an ottsentrovana and are not limited in the movement in any direction.
5. After completion of adjustment tighten lock-nuts.
6. Make sure that lengths of steering drafts are identical and that spokes of a steering wheel are correctly located at the provision of wheels directly forward.

Convergence of back wheels

The procedure of check of a convergence of back wheels the same, as described in Section. Replacement of the lower bearing of a steering column for forward wheels. The convergence of back wheels is not subject to adjustment (see Section. Removal and installation to the place of a jet bar of a back suspension bracket).