Page 631
CONTENTS
600
GENERAL
601
WHEEL ALIGNMENT
631
BALL JOINTS
632
CONTROL ARMS
641
STEERING WHEEL, STEERING COLUMN TUBE
WITH SUPPORT AND STEERING COLUMN
642
STEERING GEAR
643
TIE-ROD END ASSEMBLIES
644
POWER STEERING
SA.1'11
Page 633
GENERAL
All wheels are equipped with coil springs. The front wheels
are individually suspended and are mounted on the steering
knuckle housings, which are connected to the control arms
by permanently lubricated ball joints. T.he inner ends of the
control arms are journaled to the body in rubber bearings.
The spring movement of the wheels is limited by rubber
buffers. The lower front spring supports are pivot suspended.
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S 4344
FRONT SUSPENSION
1. Upper control arm
2. Lower spring support
3. Coil spring
4. Rubber buffer
5. Rubber buffers
6. Shock absorber
~
600-1
Page 634
STEERING KNUCKLE HOUSING
The front suspension consists of separate left-hand and
right-hand units. The steering knuckle housing, on which
the wheel is mounted, consists of a bearing housing with
two inward-curving pivot arms. The wheel is journaled
on a double-row angular contact bearing. The outer drive
shaft is splined and force-fitted to the hub. The brake
disc is mounted on the hub, and the brake shield is bolted to the steering knuckle housing. The steering arm
is fastened to the steering knuckle housing by two screws.
In steering, the steering knuckle housing pivots about an
imaginary axis, the "king-pin" or steering knuckle axis,
which passes through the centers of both the ball joints
and intersects the ground at a point close to the center
line of the wheel. The outer and inner drive shafts are
connected by the outer universal joint, which is protected
from dirt by a rubber bellows.
12
1 2
8
S 4346
FRONT AXLE ASSEMBLY
1. Lock nut
2. Washer
3. Wheel hub
4. Wheel bearing
600-2
I
5. Steering knuckle housing
6. Outer drive shaft
9. Lock ring
10. Ball
7.Hub
8. Rubber bellows
11. Upper ball joint (upper end piece)
12. Inner drive shaft
Page 635
CONTROL ARMS
The front axle, forming a separate unit on each side, is
bolted to ball joints forming the outer ends of the control arms. There are two control arms on each side, each
journaled in rubber bushings in two bearing brackets.
The upper control arms carry the coil spring supports,
which also serve as compression stops for the rubber
buffers.
1
4
5
4
~
0
S 4347
CONTROL ARMS, BEARINGS AND BUSHINGS
1. Upper control arm
2. Lower control arm
3. Rubber bushing
4. Bearings
5. Spacers
600-3
Page 636
l
STEERING MECHANISM
The steering mechanism is of the rack and pinion type
with a helical spur gear which engages a mesh on the rack.
The rack is journaled in a housing of cast light-alloy in
which a steel tube is press fitted.
The pinion bearing is provided with a spring-loaded
p!unger that presses the rack against the pinion. The
other end of the rack is journaled in a bushing. Steering- wheel movement is transmitted to the pinion by a twopiece steering column and two joints. This imparts an
axial movement to the rack, which moves the two tie
rods connected by ball joints to the ends of the rack.
The tie rods in turn move the steering arms fastened to
the steering knuckle housing and connected by ball
joints to the tie rods.
,.,..
STEERING MECHANISM
POWER STEERING GEAR
Some models are equipped with a hydraulic power steering gear.
The assembly consists of a rack-and-pinion steering gear
with a servo valve which regulates the oil flow to a servo
plunger on the rack. The hydraulic pressure is generated
by an oil pump which is driven by a V-belt from the belt
pulley on the crankshaft. A separate oil tank by the left
wheel housing supplies the system with hydraulic oil.
The steering gear is permanently lubricated with oil. A
tube running between the two ends of the steering gear
housing leads the~ubricating oil past the hydraulic portion of the rack.
600-4
SI\AB
1
Page 637
WHEEL ALIGNMENT
WARNING
When the car is on a hoist, do not seize a front wheel
and twist it by main force to full steering-wheel lock.
There is a very serious risk of damaging the steering
mechanism if this is done, as the rack-and-pinion gear
will cause t~e steering wheel to spin at high speed, im
posing a severe torsional strain on the steering col um
when the rotation is arrested by the stop in the steering gear.
CHECKING AND ADJUSTMENT
If there is reason to suspect that the front wheel alignment is faulty, which manifests itself through abnormal
tyre wear, impaired steering and road-holding characteristics, etc., the following action should be taken:
1. Check that the tires are inflated to the correct pressure
and that one front tire is not much more heavily worn
than the other.
2. Check the front wheel bearings, control arm bearings,
steering knuckle joints and tie-rod joints, and adjust or
exchange parts as necessary to eliminate any faults of
alignment that may be due to worn components.
3. Check the steering gear and make good any defects
(see section 642).
4. Check the operation of the shock absorbers and exchange damaged shock absorbers and rubber bushings.
5. If the car has been involved in a collision, era.sh, etc.,
any resulting damage must be repaired before wheel
alignment is measured. If the suspension control arms
are bent, no attempt must be made to straighten them,
they must be replaced by new ones.
6. Just before the measurements are made, the car should
be driven without hard cornering and with normal suspension movement to work the wheels into their natural positions. For the same reason, the car should be
rocked up and down a few times on its springs.
Toe-in
Seen from above, the wheels run at a certain angle to each
other. Measurements A and B, made from rim to rim level
whith the axles, must bear a given relationship to each other
(see illustration). If A is smaller than B, the wheel are said
to converge or toe in, and if A is greater than B, the wheels
diverge or toe out.
Wheel toe-in or toe-out is expressed in fractions of an inch
or milimeters, being the difference between A and B.
Toe-in is zero if the wheels are parallel, in which case both
measurements are exactly the same.
The correct toe-in is 0.08 ± 0.04 in. (2 ± 1 mm) i.e. A is
less than B by this much.
A
When the measurements are made, the car should be empty and should be standing on a flat horizontal surface; this
is the only way to get reliable readings. Adjustment with
the help of spacers must be kept within reasonable limits.
If there are any deformations due to body damage, the body must be straightened up properly. If the suspension con·
trol arms are bent out of true, they must be replaced by
new ones. For checking the wheel alignment there are various instruments, which are fitted either on the rim or directly on the axle. Each instrument has its own instruction
manual explaining exactly how it is to be used.
B
NOTE
With front-wheel-drive cars it is important that the
wheels are immobilized by the brakes while the measurements are being made in cases where the wheels
are set up on turntables or the like, or when a measuring instrument is mounted on the end of the axle.
S 4349
TOE-IN
&AMI
601-1
Page 638
Checking and adjustment by means of measuring tool:
NOTE
After adjustment of toe-in, the free length of thread
on the tie rod (length A, see illustration) must not
on any account be more than 1" (25 mm) (power
steering gear 26 mm). The free thread lengths (A)
on both tie rods must not differ from each other by
more than 0.08" (2 mm).
1. Roll the car straight forward on a level floor and stop
it without using the brakes. It must not be moved
backward after this.
2. Take a reading of measurement A with the toe-in
gauge between the front wheel rims level with the
axles. Mark the measurement points with chalk. Roll
the car forward until the chalk marks are level with
but behind the axles, and take a reading of B.
Any necessary adjustment is made by altering the
length of the tie rod.
3. Undo the nut on the outer end of the tie rod and the
outer clip on the steering gear rubber bellows.
4. Use a suitable pair of grippers to twist the tie rod right
or left; adjust until the toe-in is right. Hold the bellows
during the twisting.
For adjustment using toe-in equipment refer to the instructions accompanying the equipment.
A
25 nu,1
S3574
CHECKING THE LENGTH OF THE TIE ROD
A= 1 in. (25 mm), povver steering gear max 26 mm
Camber
Camber ist the angle by which the centerlines of the
wheels lean from the vertical (see illustration). The camber is positive (+) if the wheels lean outward, and negative (-) if they lean inward. The correct front-wheel
camber is 1/2 ± 1/2°.
ADJUSTING THE TIE ROD
NOTE
With the correct toe-in and the wheels lined up
straight ahead, both tie rods should be the same
length - or so adjusted that both wheels have the
same clearance to the fenders and wheel housings
at full right and left lock respectively. Check also
that the steering wheel spokes are horizontal when
the front wheels are pointing straight ahead. Do
not forget to tighten the tie rod nut after adjusting.
S 4351
CAMBER
601-2
SAM5
Page 639
The camber, and with it the "king pin" angle, can be adjusted with spacers placed under the two bearing brackets
of the upper control arms. The desired result can thus be
obtained by increasing or reducing the number of spacers
used. To increase or reduce camber, use the same number
of spacers under both brackets. The rear bearing bracket
is available in a lower design that gives bigger adjustment
possibilitys. See the spare parts catalogue.
If the caster angle needs adjusting, this is done with the
help of spacers placed under the bearing brackets of the
upper control arms.
To increase the caster, transfer spacers from the front
bracket to the rear bracket.
To reduce the caster, transfer spacers from the rear bracket
to the front bracket.
In either case, the total spacer thickness removed from
one bracket must be added to the other one.
Spacers for caster adjustment are supplied in thicknesses
of 0.5, 1.0 and 2.0 mm (0.02", 0.04" and 0.08").
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The car does not have king pins as such; the wheels pivot
on two ball joints instead. It is thus more correct in this
case to speak of the steering knuckle axis, i.e. the line
passing through the centers of the ball joints and intersecting the ground near the wheel centerline. The steering
knuckle axis should incline sideways from the vertical by
11 1/2 ± 1°.
LOCATION OF CAMBER ADJUSTMENT SPACERS
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Caster
The caster is the angle by which the king pin axis (or, in
the case of the models 99, the steering knuckle axis) departs from the vertical when viewed from the side and is
generally expressed in degrees. Caster varies a great deal
from one type of car to another, although in most cases
the "king pin" leans backward as illustrated below; in
such cases the caster is said to be positive(+), whereas if
the "king pin" leans forward the caster is negative (-).If
the "king pin" is vertical, the caster is zero. The correct
caster angle is: manual steering gear 1°± 1/2°
power steering gear 2°±112°
S 4354
"KING PIN" ANGLE
When the wheel camber is adjusted, the inclination of the
steering knuckle axis is automatically altered by the same
amount at the same time. The latter angle cannot be adjusted independently, as it is determined by the dimensions of the steering knuckle housing. If the steering knuckle axis is found to be out of true when the camber is correctly adjusted, this indicates that there is something
wrong with the steering knuckle housing, which snould
therefore be exchanged.
S 4353
CASTER
SAAB
601-3
Page 640
Wheel turning angles
Wheel alignment which allows perfect running of all four
wheels on bends varies somewhat depending on speed
and the sharpness of the bend owing to suspension movement and tire deformation.
The turning angles have been adapted to the most common driving conditions.
As the tie-rods point slightly inwards in relation to the
travelling direction (driving straight ahead), the steering
angle of the inside wheel on a bend will be slightly greater.
I
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S4356
CORNERING POSITIONS OF FRONT WHEELS
601-4
SAAB