Page 421
472-2
Automatic Transmission Seals and Gaskets
Automatic Transmission Fluid Cooler
/
The cooler should be replaced if it is visibly leaking. The cooler can also leak internally, causing the engine coolant to mix
with the ATF. When this happens, the ATF usually has a milky
appearance.
To replace ATF cooler
1. Drain the engine coolant as described in 261 Radiator
and Cooling System.
2. Disconnect the coolant hose clamps and the ATF hoses. Then remove the cooler. See Fig. 2. Some models
are equipped with an ATF thermostat in-line with the
ATF cooler.
ATF cooler connection nut
·13 to 16 Nm (10 to 12 ft-Ib)
Installation is the reverse of removal. Always replace 0rings and gaskets. Be sure to top up the ATF.
CAUTION
• Always replace the ATF and flush out all ATF hoses if coolant
contamination has occurred.
• If a reconditioned transmission is being installed, flush out
the ATF cooler and hoses with clean ATF.
GENERAL
Fig. 2. ATF cooler. Arrows show coolant hose clamps and ATF
hoses to be removed.
Page 422
Brakes-General
500-1
500 Brakes-General
General
500-1
Anti-lock Braking System (ABS)
500-2
To replace ABS wheel speed sensor . . . . . . . 500-3
GENERAL
All cars covered by this manual are equipped with disc
brakes at all four wheels. See Fig. 1. The brake system is hydraulically actuated by the master cylinder and has power assist. The brakes are self-adjusting. The parking brake system
is mechanical using cables connected to the calipers. Some
later models are equipped with an anti-lock braking system
(ABS).
Models without ABS use a vacuum booster for power assist. Models with ABS provide power assist through the ABS
unit.
Brakes Troubleshooting
500-5
TABLES
a. Brake Troubleshooting
500-6
The brake disc, also known as the rotor, is mounted to each
wheel hub. Two brake pads, one on either side of the disc are
located within the caliper. The caliper piston applies force to
the brake pads. When the brakes are applied, the friction-surfaced brake pads slow the car. See Fig. 2. A combination of
flexible and rigid brake lines connect the calipers to the hydraulic system and master cylinder.
The brake pedal directly actuates the master cylinder. The
master cylinder creates pressure in two hydraulic circuits. The
two hydraulic circuits form the dual-diagonal braking s~ste~
where diagonally opposite wheels are braked by one CirCUIt.
The system assures a level of braking control if one circuit
should fail.
6
6
Brake pedal
Brake vacuum booster
Master cylinder
Front wheel caliper
5. Rear wheel caliper
6. Brake disc
7. Parking brake lever
7
6
6
87921>$51448 _
Fig. 1. Four wheel disc brake system
GENERAL
Page 423
500-2
Brakes-General
The ASS system can be simplified into four basic components that operate in a closed loop. See Fig. 4. The wheel
speed sensors at all four wheels measure wheel speed. The
control unit constantly compares these signals to determine
when one wheel is not rotating at the same speed as the others-indicating a potential lock-up condition. Using this information, the control unit regulates the opening and closing of
the solenoid valves to adjust the fluid (hydraulic) pressure to
the calipers.
0)
II
,
87926
Rg. 2. Brake disc and caliper. Airflow over the brakes (arrows) helps
cool the caliper and disc.
CD
ANTI-LOCK BRAKING SYSTEM (ABS)
The ASS system, used on some late models, was developed to ensure optimum braking ability under widely varying
road and weather conditions. See Fig. 3. The system monitors
and automatically controls braking at the front wheels individually and the rear wheels as a pair-preventing the wheels
from locking during emergency braking situations. Steering
control is maintained during braking and the shortest possible
stopping distance is achieved. The ASS system only operates
during emergency stops or hard braking. During most normal
braking situations, the system is not in operation.
3. Pressure regulator
in ABS unit
4. Brake caliper
Fig. 4. Basic representation ABS system closed-loop operation.
1
1
1. Wheel speed sensors
2. ABS unit
3. ABS electronic control unit
87929
1. Wheel speed sensor
2. Control unit
1
Rg. 3. Schematic of ABS system.
ANTI-LOCK BRAKING SYSTEM (ABS)
3
2
1
87928-551165
Page 424
Brakes-General
The ABS unit is shown in Fig. 5. The pump pressurizes the
accumulator to provide power assist normally provided by the
vacuum booster. The accumulator holds enough pressure in
the system to provide power assist for approximately twenty
stops if the pump should fail. The ABS system is able to monitor itself and if there is a sensor or control system failure it will
revert to the non-ABS mode.
500-3
WARNING
On cars with ABS, dangerously high pressure may be retained
in the system, even though the car is not running or has not
been driven recently. Before loosening any components, depressurize the system by disconnecting the battery negative
cable and pressing the brake pedal 25 to 30 times, or until
there is a noticeable increase in pedal effort. Never attempt to
open the pressure accumulator.
NOTE
For information on replacing the ABS unit, see 521 Brake
Master Cylinder. For ABS wiring and ABS wheel speed sensor testing, see 371 Wiring Diagrams, Fuses and Relays
NOTE
The control unit has the capability to detect and store fault
codes, although retrieving these faults codes requires special
test equipment. See an authorized Saab dealer for additional
information on ABS fault codes.
To replace ASS wheel speed sensor
Replacement of wheel speed sensors is similar for either
the front or the rear. The sensor is a sealed unit and cannot be
repaired. Be sure to have a new fiber washer on hand when
removing or replacing the sensor. The washer is used to precisely set the air gap between the sensor and the toothed
wheel.
1. Working in the engine compartment, disconnect the
negative battery cable and the wheel speed sensor
connectors. See Fig. 6.
NOTE
The wheel speed sensor connectors for the rear wheels are
located under the rear seat.
87930-85/172
1. Brake fluid reservoir
2. Pump
3. Accumulator
4. Master cylinder
-------
-
---
Fig. 5. ABS unit.
The ANTI-LOCK and the BRAKE FLUID warning lamps in
the instrument cluster monitor the system. The ANTI-LOCK
warning lamp will light up if a problem or fault occurs in the
ABS system. The BRAKE FLUID warning lamp will light up if
the brake fluid level in the reservoir falls too low. See an authorized Saab dealer if either warning lamps come on.
WARNING
If the ANTI-LOCK and the BRAKE FLUID warning lamp
should come on, the car must not be driven. Brake failure may
occur. Have the problem corrected promptly by an authorized
Saab dealer.
Fig. 6. Location of front wheel speed sensor connectors (arrows).
2. Raise the car and support it with jackstands. Remove
the road wheels.
WARNING
Make sure the car is well supported with jackstands. Never
use just a jack to support a car.
ANTI-LOCK BRAKING SYSTEM (ABS)
Page 425
500-4
Brakes-General
3. Remove the sensor harness from the steering member.
Carefully pull the sensor lead through the rubber grommet in the wheel arch. See Fig. 7.
NOTE
The rubber grommets for the rear wheel speed sensors are located in the floor pan and can be found by tracing the harness
from the wheel.
Fig. 9.
Rear wheel speed sensor retaining screw being removed.
NOTE
When removing rear wheel speed sensors, remove the parking
brake cable guide from the suspension spring link then remove
the wheel speed sensor hamess from the clips. See Fig. 11.
Fig. 7.
Front ABS wheel speed sensor harness guide A and rubber grommet B.
4. Remove the wheel speed sensor. See Fig. 8 and Fig. 9.
Fig. 10. Plastic sleeve being removed from sensor housing.
6. Clean out the sensor housing in the steering member
or axle. Spin the wheel hub slowly and clean out any
debris in the toothed wheel.
Fig. 8.
Front wheel speed sensor retaining screw being removed.
5. Remove the plastic sleeve from the sensor housing.
See Fig. 10.
ANTI-LOCK BRAKING SYSTEM (ABS)
7. Working at the bench, clamp the sensor adjusting
sleeve in a vice and remove the setscrew. See Fig. 12.
Remove the sensor from the adjusting sleeve.
CAUTION
Clamp only the sensor sleeve. Do not clamp the metal part of
the sensor, as this will damage it.
Page 426
Brakes-General
500-5
CAUTION
The fiber spacer has a thickness of 0.6S mm to provide the
sensor with the proper clearance to the toothed wheel. Do not
spin the toothed wheel until the sensor has been completely
installed. If the fiber washer is damaged, the sensor may be
incorrectly installed.
Specification
• ABS wheel speed
sensor air gap
Fig. 11. Parking brake cable guide (A) and wire harness clip (8)
holding wheel speed sensor harness to rear suspension
spring link.
0.65 mm (0.026 in.)
10. Install the wheel speed sensor and tighten the retaining
screw. See Fig. 8 or 9 above.
11. Gently press the sensor body against the sensor wheel
then tighten the setscrew.
The remainder of installation is the reverse of removal.
Check that the ABS warning light comes on for several seconds when starting the engine. It should then go out.
BRAKES TROUBLESHOOTING
This troubleshooting section applies mainly to the mechanical and hydraulic components regardless of whether or not
the car is equipped with ABS. It is important to realize that
ABS only operates when one or more wheels are about to lock
during emergency or otherwise hard braking. It is very unlikely
that ABS components are the cause of more conventional
brake noise or grabbing symptoms.
Fig. 12. Setscrew being removed from wheel speed sensor
sleeve.
8. Clean any debris from the end of the wheel speed sensor and sensor sleeve using a wire brush. Lightly lubricate the sensor body.
9. Glue a new fiber spacer to the tip of the wheel speed
sensor. Install the new sensor in the sensor sleeve.
NOTE
This troubleshooting section does not specifically include
troubleshooting for ASS. If an ASS system fault exists, see an
authorized saab dealer who has the necessary training and
diagnostic equipment to properly service the system.
The most common brake problems and repairs involve the
brake calipers, pads, and brake discs since these components are exposed to heat, water, chemicals, and corrosion.
BRAKES TROUBLESHOOTING
Page 427
500-6
Brakes-General
Table a. Brake Troubleshooting
Probable cause
Symptom
1. Brake squeak or
squeal
2. No brakes, pedal
goes to floor
I
Corrective action
a. Nonnal condition
a. See 516 Brake Discs
b. Brake pads installed incorrectly
b. Check installation. 517 Brake Pads
c. Calipers or brake pads binding,
brake caliper guide pins or caliper
dirty or corroded
c. Clean calipers and/or guide pins. 523 Brake Calipers, 517
Brake Pads
d. Brake pad lining wom
d. Install new pads. 517 Brake Pads
e. Brake pad linings heat-glazed or oilsoaked
e. Replace brake pads. Clean discs. Replace leaking calipers as
required. 517 Brake Pads, 516 Brake Discs, 523 Brake Calipers
a. Brake fluid level too low
a. Check fluid level. Check for leaks. Fill and bleed system. 520
Brake Fluid and Brake Bleeding
b. Master cylinder faulty
b. Replace master cylinder. 521 Brake Master Cylinder
c. Failed line or hose, loose union, or
other major fluid leak
c. Check for leaks. Fill and bleed system. 522 Brake Lines
3. Low pedal, (brakes
properly bled, no
signs of leakage)
a. Master cylinder faulty
a. Replace master cylinder. 521 Brake Master Cylinder
4. Pedal feels spongy
or brakes work only
after pedal is
pumped
a. Insufficient brake fluid
a. Check fluid level. Check for leaks. Fill and bleed system. See
520 Brake Fluid and Brake Bleeding
5. High pedal effort
required (braking
perfonnance poor)
6. Brakes pulsate,
chatter, or grab
7. Uneven braking, car
pulls to one side
8. Brakes drag, bind,
or overheat
9. Brakes make loud
clunk when backing
up
b. Air in brake fluid
b. Bleed system. 520 Brake Fluid and Brake Bleeding
c. Master cylinder faulty
c. Replace master cylinder. 521 Brake Master Cylinder
d. Leaking line and hose unions
d. Check for leaks. Fill and bleed system. 522 Brake Lines
a. Brake pads wet
a. Use light pedal pressure to dry brakes while driving.
b. Brake pads heat-glazed or oil-soaked
b. Replace brake pads. Clean discs. Replace leaking calipers as
required. 517 Brake Pads, 516 Brake Discs, 523 Brake Calipers
c. Vacuum booster or vacuum
connections faulty (non-ABS cars
only)
c. Inspect vacuum lines and check valve. Test booster and replace
as required. 541 Brake Vacuum Booster
d. Faulty master cylinder
d. Replace master cylinder. 521 Brake Master Cylinder
a. Warped brake discs
a. Recondition or replace discs. 516 Brake Discs
b. Recondition brakes. 517 Brake Pads
b. Brake pads wom
c. Brake pads heat-glazed or oil-soaked
c. Replace brake pads. Clean discs. Replace leaking calipers as
required. 517 Brake Pads, 516 Brake Discs, 523 Brake Calipers
a. Incorrect tire pressures
a. Check and correct tire pressures. See 1 LUBRICATION AND
MAINTENANCE
b. Brake pads heat-glazed or oil-soaked
b. Replace brake pads. Clean discs. Replace leaking calipers as
required. 517 Brake Pads, 516 Brake Discs, 523 Brake Calipers
c. Brake caliper or brake pads binding
c. Clean and recondition brakes. Check parking brake adjustment.
517 Brake Pads, 516 Brake Discs, 523 Brake Calipers, 551
Parking Brake
d. Brake fluid contaminated
d. Drain, flush, refill, and bleed brake system. 520 Brake Fluid and
Brake Bleeding
e. Wom tires or suspension
components
e. See 6 STEERING AND WHEEL ALIGNMENT, 7 SUSPENSION
a. Parking brake dragging
a. Adjust parking brake. Replace caliper or caliper retum spring.
551 Parking Brake
b. Brake caliper or brake pad binding
b. Clean and recondition brakes. 517 Brake Pads, 516 Brake
Discs, 523 Brake Calipers
c. Master cylinder faulty
c, Replace master cylinder. 521 Brake Master Cylinder
a. Caliper yoke wom
a. Replace caliper assembly. 523 Brake Calipers
b. Caliper guide pins wom or pre-set
b. Replace guide pins. 523 Brake Calipers
bend in pin no longer exists
BRAKES TROUBLESHOOTING
Page 428
Brake Discs
516-1
516 Brake Discs
General
TABLES
516-1
Inspecting and Replacing
Brake Discs
a. Front Brake Disc Applications
b. Rear Disc Specifications
c. Front Disc Specifications
516-1
516-2
To remove brake disc
GENERAL
516-1
516-1
516-1
Splash shield
Fig. 1 is an exploded view of the front disc brake. Two types
of front discs-ventilated and solid-are used on cars covered by this manual, depending on models and model year.
See Table a. The rear discs are solid on all models. The brake
disc is bolted to the wheel hub and can be removed once the
caliper is removed.
Table a. Front Brake Disc Applications
Model year and Model
Disc type
1985 through 1987900
Solid
1985 and 1986 900s
Ii Solid
1985 Turbo
Solid
1987900s
Ventilated
1986 through 1987 Turbo,
including convertible
Ventilated
1988 and later, All
Ventilated
Locating stud
(1988 and later)
Fig. 1. Front disc assembly (ventilated front disc shown).
Brake discs must be replaced when they cannot be resurfaced without exceeding the specified minimum thickness given below.
Discs and brake pads are subject to the greatest wear and
are the components most often requiring service. While it possible to restore the brakes by replacing only the brake pads,
the discs should be resurfaced or replaced at the same time to
achieve full braking performance and to maximize pad life.
Brake discs that are glazed or lightly scored may be resurfaced. Cracked discs should always be replaced. Discs
should be replaced or resurfaced in pairs only. If the disc is being resurfaced, both faces should be resurfaced by equal
amounts. See Table b and Table c for disc specifications.
INSPECTING AND REPLACING
BRAKE DISCS
Table b. Rear Disc Specifications
Inspecting the brake discs should be done during regular
service or when the brakes are reconditioned. The discs
should be checked for cracks, scoring, glazing and warpage.
thickness (new)
9.0 mm (0.354 in.)
thickness (wear limit)
7.0 mm (0.276 in.)
brake surface lateral runout
(maximum)
0.1 mm (0.004 in.)
Table c. Front Disc Specifications
Solid disc
Ventilated disc (1986-1987)
Ventilated disc (1988 and later)
thickness (new)
12.7 mm (0.50 in.)
20 mm (0.784 in.)
23.5 mm (0.93 in.)
thickness (wear limit)
11.2 mm (0.441 in.)
I 18 mm (0.709 in.)
21.5 mm (0.85 in.)
brake surface lateral runout
(maximum)
0.1 mm (0.004 in.)
! 0.1 mm (0.004 in.)
0.08 mm (0.003 in.)
I
INSPECTING AND REPLACING BRAKE DISCS
:;:;:::;:;=;:::;:;::::::=:.
II:
Page 429
516-2
Brake Discs
NOTE
If the brake pads are soaked with oil, grease, or brake fluid,
the cause of the contamination must be found and corrected
before new brake pads or discs are installed.
To remove brake disc
New replacement brake discs should be cleaned with a
grease-free solvent, such as brake cleaner, before installing
the caliper and brake pads. The procedure below applies to
front and rear brake discs.
1. Raise the car and support it with jackstands. Remove
the wheel.
Fig. 2. Caliper removed from disc and suspended using stiff
wire.
WARNING
Make sure the car is well supported with jackstands. Never
use just a jack to support a car.
2. Remove the brake pads as described in 517 Brake
Pads.
WARNING
Friction materials in the brake pads may contain asbestos fibers. Avoid breathing any asbestos fibers or dust. Always use
a respirator. Do not create dust by grinding or sanding, or by
cleaning the pads or disc with compressed air.
3. Without removing the flexible brake hose, remove the
caliper as described in 523 Brake Calipers. Suspend
the caliper from the body using stiff wire. See Fig. 2.
CAUTION
Do not allow the removed caliper to hang by the flexible brake
hose.
NOTE
If the brake hose remains connected, it will not be necessary
to bleed the brakes.
4. Remove the disc mounting screws or road wheellocating stud (where applicable). See Fig. 3.
INSPECTING AND REPLACING BRAKE DISCS
Fig. 3. Arrows show locating stud and disc mounting screw.
NOTE
• On 1985 through 1987 models, the disc is mounted with two
screws. On 1988 and later cars, the disc is mounted with a
screw and a locating stud.
• Use a penetrating oil in advance to help loosen corroded
screws. Keep penetrating oil away from rubber parts.
5. Remove the brake disc from the wheel hub. See Fig. 4.
NOTE
If the disc is frozen to the hub, tap it loose with a soft faced
mallet.
•
Page 430
Brake Discs
516-3
Tightening torques
Fig. 4. Disc being removed from hub.
Installation is the reverse of removal. Use a new caliper
mounting bolt locking plate when installing the caliper. Reinstall the brake pads and gently pump the brake pedal several
times to seat the pads on the disc. Install the wheels and tighten the wheel lugs. Test the footbrake and parking brake functions.
• front brake caliper to
steering member
110 to 130 Nm (81 to 96 ft-Ib)
(1985 to 1987)
• front brake pad carrier
to steering member (1988
models and later) ..... 70 to 110 Nm (52 to 81 ft-Ib)
• rear brake caliper to axle
(1985 to 1987)
70 to 90 Nm (52 to 66 ft-Ib)
• rear brake pad carrier to axle (1988 models
40 to 54 Nm (30 to 49 ft-Ib)
and later)
• road wheel locating stud
to wheel hub
25 to 30 Nm (18 to 22 ft-Ib)
• wheel to wheel hub
lug nuts
90 to 110 Nm (66 to 88 ft-Ib)
lug bolts
105to125Nm(77to92ft-lb)
• all other fasteners
M5 bolt
5 Nm (44 in-Ib)
M6 bolt
10 Nm (89 in-Ib)
M8 bolt
20 Nm (15 ft-Ib)
M10 bolt
40 Nm (30 ft-Ib)
INSPECTING AND REPLACING BRAKE DISCS