Page 501
UNIVERSAL JOINTS
Inner universal joint
The inner universal joint consists of a driver journaled in
the differential housing and splined into the differential
side gear. It is locked to the differential side gear bya
resilient lock ring fitting into a groove inside the side gear.
When the driver is inserted or withdrawn, the ring expands
into its groove.
INNER UNIVERSAL JOINT, UP TO MODEL 1969
INNER UNIVERSAL JOINT, AS FROM MODEL 1970
The outer end of the driver takes the form of a fork in
which the drive shaft is journaled in needle bearings (see
illustrations). When the car is in motion, the drive shaft
can slide axially as well as being jointed. The joint is packed
with grease and shielded by a rubber bellows.
Lubrication is needed only when the joint is reconditioned
or removed for some other reason. Saab Special chassis
grease must be used.
Removing
1. Jack up the front of the car and take off the wheel.
2. Remove the brake housing and hang it up by the
wheel housing to avoid strain and damage to the
brake hose; then remove the brake disc and parking
brake assembly with cable.
3. Undo the large clamp from the rubber bellows on the
inner universal joint.
To separate the inner universal joint, fit protection
covers in the rubber bellows and on the inner driver.
Universal joints, earlier design: Use cover 732373 in
the rubber bellows and 783846 on the driver.
Universal joints, later design: Use cover 834458 in the
rubber bellows and 891696 on the driver.
[sires
REMOVING THE STEERING ARM
Tool No. 899540
a
4. Disconnect the tie rod from the steering arm using
tool 899540 and undo the nut on the upper ball joint.
Remove the screws from the lower control arm bracket.
5. Pull out the drive shaft through the wheel housing and
remove the entire front axle assembly.
6. Disconnect the driver from the transmission with aid
of tapping hammer 839027 and puller 839147 alt.
879035 depending on shaft design.
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REMOVING THE INNER DRIVER
Tools 839027 and 839147
7. If the rubber bellows on the inner or outer universal
joint needs renewing, detach the shaft from the outer
joint (see “Outer universal joints’). The rubber bellows
can then be slipped off the shaft.
Dec. 1975 SAAB 475-1
Page 502
Mounting
1. Make sure that the inner driver is washed clean, and
then pack the needle bearing seats with Saab Special
chassis grease. The right amount will be obtained if
the driver is filled with grease.
2. Mount the inner driver by pushing it into the differen-
tial housing. Make sure that the lock ring in the differ-
ential side gear engages properly.
3. Slip the rubber bellows over the drive shaft and mount
the shaft and rubber bellows to the outer universal
joint (see “Outer universal joints’’).
4. Pack the needle bearings with Saab Special chassis
grease and fit the bearings over the tee ends of the
drive shaft. Mount protection cover in the rubber
bellows to protect the bearings and prevent them
from falling off. Then insert the shaft complete with
rubber bellows through the wheel housing.
5. Take the cover out of the rubber bellows and slide the
drive shaft complete with needle bearings into the inner
driver. Locate the rubber bellows and put on the clamps.
. Mount the steering knuckle housing and steering arm.
. Mount the parking brake assembly with handbrake
wire, the brake disc and the brake housing.
8. Mount the wheel and lower the front of the car.
“ND
:
IMPORTANT
After the brake housing has been mounted the brake
pads must be advanced to their correct positions
close to the disc by repeated pumping of the foot-
brake pedal. Otherwise the footbrake will not work.
Outer universal joints
General
On the outer universal joints the outer drive shaft termi-
nates in a bell with a spherical track in which six balls
transmit the driving power from a hub. The inner drive
shaft is splined into the hub and located in it by a resil-
ient lock ring. To mount the shaft in the hub, the lock ‘
ring is first compressed with a special tool 784161 and
the shaft is then inserted. For removing, the shaft is
knocked out of the hub with a special tool 784202. Only
the complete outer drive shaft assembly, including hub,
ball retainer and balls, is supplied as a replacement unit. \
Its component parts are individually matched and are not .
interchangeable.
The joint needs lubricating only in conjunction with re-
conditioning or if disassembled for any other reason. Use
Saab Special chassis grease.
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OUTER UNIVERSAL JOINT
. Castle nut 6. Spacer sleeve 11. Hub
Washer 7. Inner shaft seal 12. Rubber bellows
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475-2 SAAB
. Wheel hub 8. Outer drive shaft
. Outer shaft seal 9. Lock ring
. Wheel bearing 10. Ball
13. Inner drive shaft
Dec. 1975
Page 503
Disassembling
1. Take off the hub cap, remove the split pin and castle
nut and back off the wheel nuts.
2. Block up the front end of the car and take off the
wheel.
3. Take off the brake housing and hang it up to avoid
damage to the brake hose. Remove the brake disc
and disconnect the handbrake cable.
REMOVING THE STEERING ARM
Tool 899540
Universal joints, later design: Use cover 834458 in
the rubber bellows and 891696 on the driver.
6. Pull out the drive shaft through the wheel housing
and remove the entire front axle assembly, which
should then be cleaned thoroughly. Take the large
clamp off the outer universal joint.
$1728
IMPORTANT
BRAKE HOUSING HUNG UP DURING WORK ON WHEEL Be careful not to damage the guard plate.
7, Pull off the wheel hub using tool 819518 and re-
move the outer drive shaft with the joint and inner
drive shaft.
4, Undo the large clamp the rubber bellows of the inner
universal joint.
5. Free the steering arm and the upper ball joint using
tool 899540. Undo the screws on the lower control
arm bracket. ;
To separate the inner universal joint, fit protection r =
covers in the rubber bellows and on the inner driver. :
Universal joints, earlier design: Use cover 732373 in
the rubber bellows and 783846 on the driver.
REMOVING THE WHEEL HUB
Tool 899518
REMOVING THE UPPER BALL JOINT
Tool 899540
Dec. 1975 SAAB 475-3
Page 504
Assembling
41. Mount the front axle assembly in a press. Press the
outboard drive shaft into the steering knuckle hous-
ing (see illustration).
PRESSING IN THE OUTBOARD DRIVE SHAFT IN A PRESS
2. Put on the castle nut, tighten it to a torque of 196 Nm
(145 ft.lb., 20 kpm) and lock it with the split pin.
Pack the joint with grease, fit both clamps on the
outer rubber bellows and the smaller shaft clamp
on the inner rubber bellows. If the needle bearings
have been removed, lubricate them with Saab
Special chassis grease and mount them on the ends
of the tee. Fit protection cover into the rubber
bellows to protect the needle bearings and insert
the drive shaft through the wheel housing. Make
sure that the inner driver is clean and packed with
fresh Saab Special chassis grease. Assemble the
inner universal joint. Mount both ball bolts to the
steering knuckle housing and tighten them to the
prescribed torque. Fasten the clamp round the inner
joint bellows.
3. Mount the brake disc, handbrake cable and brake
housing.
4. Mount the steering arm and put on the wheel.
5. Lower the front of the car, tighten the wheel nuts
securely and fit the hub cap.
CAUTION
The brake pads must be brought back to their prop-
er position close to the disc, which is done by pump-
ing the brake pedal repeatedly. Otherwise the brake
will not work.
475-4 SAAB
Dec. 1975,
Page 505
Nov. 1969
CONTENTS
516
517
520
521
522
523
524
General
Brake discs
Brake pads
Hydraulic footbrake system
Master cylinder
Brake lines
Wheel cylinders and brake housings
Brake control
Handbrake system
Page 506
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Page 507
GENERAL
The car has two mutually independent brake system: the
footbrake or driving brake, which is hydraulic and acts on
all four wheels, and the handbrake or parking brake, which
is mechanical and acts on the front wheels through drums
in the disc brake hubs.
The footbrake system has two separate circuits. The mas-
ter cylinder acts simultaneously but independently on
each diagonally opposed pair of wheels, i.e. right front +
left back and left front + right back. Thus if the system
is damaged and brake fluid leaks out, braking power will
be lost on one diagonal pair of wheels only, the other
pair being unaffected. A leak can be detected by abnor-
mally long pedal travel and a tendency for the car to pull
the side that still has braking power on the front wheel.
The front wheel cylinders have a larger bore than the rear
wheel cylinders, with the result that braking power is
greater on the front wheels; this reduces the risk of the
back wheels locking and skidding.
The footbrake system has a power assist from a cylinder
connected to the engine inlet-manifold. When the brake
pedal is depressed it acts on the master cylinder via the
power assist; the latter increases the pedal pressure and
transmits the motion to the master cylinder.
The handbrake is located between the front seats; opera-
tion of the lever is transmitted mechanically by cables.
In the instrument panel there is a warning light that
shows red if the handbrake is on or if the pedal goes
too far down, because of brake fluid leakage.
S1770
BRAKE SYSTEM, GENERAL LAYOUT
Power assist
Brake pedal
Handbrake lever
Pa sale ae ol 5 ra
Jan, 1971
Master cylinder with brake fluid container
Disc brake assembly, front wheel
Brake shoes, handbrake
Disc brake assembly, rear wheel
500-1
Page 508
Two-circuit brake system — functioning
When the brake pedal is depressed, the pistons in the mas-
ter cylinder generate pressure in the brake fluid. The pres-
sure in the brake fluid. The pressure is transmitted through
the brake lines and hoses to the cylinders at the wheels,
where the pistons force the brake pads against the discs.
The master cylinder has two pistons each serving one cir-
cuit. If a leak occurs in either circuit, the piston in that
circuit moves without affecting the brake pads; thus every
time the brake pedal is pressed, a certain amount of fluid
is pumped out of the system. However, as the fluid con-
tainer is divided into two independent compartments, on-
ly one compartment can be emptied, and enough fluid
remains in the other compartment to drive the car safety
to the nearest workshop. As the two circuits are arranged
diagonally, roughly half the normal braking power is al-
ways retained if one circuit develops a leak. This system
also makes the car safer to steer because one front wheel
and one rear wheel turn freely without locking.
Master cylinder
The master cylinder is of tandem type, consisting of a
housing in which a primary piston and a secondary or in-
termediate piston are actuated by the push rod from the
brake pedal. The distance between the pistons is con-
trolled by a coil spring and a screw. The secondary piston
has three seals, one at the front and two at the rear. Be-
hind the front seal is a domed washer that prevents the
seal from floating out into the filler holes in the flange
of the piston. The primary piston likewise has a front seal
with a domed washer and two rear seals.
The coil springs serve to return the pistons to their start-
ing position. When at rest, the pistons are pushed back-
ward by the spring and the channels between the fluid
container and master cylinder are open. When the brake
pedal is pushed down, the push rod moves the primary
piston which closes the feed channel from the fluid con- \
tainer to the cylinder; the pressure ahead of the primary
piston rises and acts to move the secondary piston, where-
upon the same positive pressure is generated ahead of both
pistons. The result is that brake fluid is forced out through
the brake lines to the wheel cylinders and the brakes are
applied. \
\f for example leakage occurs in the primary circuit, the
primary piston spring is compressed until the primary
piston works upon the secondary piston, whereupon the
latter acts on the brakes in the secondary circuit. If there
is a leak in the secondary circuit, the secondary piston is
pushed forward by the primary piston until it strikes the
——-->---————_, end of the cylinder, after which brake fluid can be forced
| | | out into the undamaged circuit.
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$1721
SECTION THROUGH MASTER CYLINDER
1, Container 8. Sleeve
2. Rubber seal 9. Screw
3. Housing 10. Lock ring
4. Secondary piston 11. Seal ring
5. Spring 12. Primary piston
6. Piston seals 13. Screw
7. Washer
Jan, 1971
Page 509
The disc brake assembly (see fig.) consists of a brake hous-
ing divided into two halves which are bolted together. Each
half contains a brake cylinder, and the housing fits round
the brake disc.
The brake assemblies on the front wheels are mounted on ———S NS
the steering knuckle housings, while the rear wheel brakes
are attached to special fastening points on the rear axle.
When the brakes are applied, the pistons push the pads
against the disc. A bleeder nipple is provided at the highest
point of the brake housing.
The cylinder has piston seals, which serve both to
prevent brake fluid from leaking out and to return
the pistons to their starting positions after braking. This
return action is normally enough to prevent the pads from
PP rubbing against the disc.
J Up to and incl. model 1971, the front wheel brake
pistons are provided with disc throw compensators, to
prevent the pistons from going back to far after braking.
However, it has shown that this device is not necessary,
and it has therefore been taken away as from model $ 1723
} 1972.
THE BRAKE PISTON IS RETURNED TO REST BY THE
ACTION OF THE PISTON SEAL
Wheel brakes ‘ \N
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Rest position
Braking position
BRAKE HOUSING
1. Disc throw compensator, up to and incl. model 1971
BRAKE ASSEMBLY, FRONT WHEEL
1. Brake housing half 7. Brake pad
2. Piston seal 8. Locking pins
3. Piston 9. Brake housing half
4. Gasket 10. Brake drum and disc
5. Gasket.retainer 11. Bleeder screw
6. Retaining spring
Sept. 1973 SAAB 500-3
Page 510
Handbrake
The handbrake acts on separate drums on the front wheels.
The handbrake lever is located between the front seats and
jts action is transmitted mechanically by wires.
The upper ends of the brake shoes are held pressed against
the support piece (1) by the upper tension spring (3). The
lower ends are joined by the adjusting device (6)and are
held against it by the lower spring (7). This form of suspen-
sion makes the brake shoes self-centering and both of them
are partly self-applying. The brakes are thus of the Duo
Servo type.
The brake shoes should be replaced when the thickness of
the very lining is less than 0.02” (0.5 mm).
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HANDBRAKE, FUNCTION
1. Support piece
2. Lever
3. Upper tension spring
4. Holding spring
5, Primary brake shoe
6. Adjusting device
7. Lower tension spring
8. Brake drum
9. Brake lining
10. Compression spring and locking pin
11, Secondary brake shoe
12, Pressure rod
Brake cables
The brake cables are permanently lubricated and consist
of steel wires in plastic coated spiral sheaths which run
through grommets in the dash panel and wheel housings
to the externally placed levers where the wires are con-
nected by crosspieces and nuts. A return spring is located
between the operating lever and the guard plate. The in-
ner ends of the wires are fastened to the handbrake lever
adjusting device.
Jan. 1972