Scania Brake Service Manual

10:00-01

Issue 2 en

Brake Diagram Manual

B6

SK 6

35

3

MAD 16

27

11

12

4

SJ 6

52

28

61d

6

PG

10b

17

12

21

11

22

16

12

16

65

84

10a

MP 6

16

MK 6

MV 16

MA

MAM

6

4

74

22

1

MU 8

PZ 12

B2

21

13

55

PH 6
PE

BCC 6
FAF 12
FBO 6

XCF 12

55

PK 6

B1

8

8

B5

PC
BAF 12
BAG 12
FBC 12
FAG 12

16

MAO

1

58c

19

XCE 12

B3

Opt.

PO 6

55

36

36

3236323632

MBK 12 MBJ 12 MBH 12

Opt.

39

2

55

55

FB

12

51

1

7k

FAV 12

FBS 12

FA 12

1

51

22
21

11
23
24

4

BA 12

PA 12

XM 12

57

12

22

11

41

42

43

SAV 8

55

Middle valve unit

27

4

11

12

55

1

2

58a

83

PCD 12PCC

12

12

PX

2

27

12

19b

21

1

2

22

4

2

SAU 8

12

11

55

23

7c

BCG 8
BCF 12
PBX
PBU 6
PBW 12

58b

PBZ 12
PBS

PBT 6

FBR 8
SAP
SAR
SAS 12

XCJ 12
BCK 12

49

12

4

1

2

7d

3

79

BYC 6

32

6
B

BC 12

Y
B

7d

32

32

12

1

PBV 12

8

6
6

BYD 8

BCL 12

B3

BK

8

BAG

A3

12

PCF

B4

12

A2

PO

6

PCB

B6

12

PA 12

A1

8

PC

A5

PK

6

A4

FBS

8

B5

SK

6

A6

SX

12

B2

12

SC

B1

4

27

55

2

BL 8

PF 12

51

1

19

51

2

7b

32

18

PD 12

55

55

4

27

5

6

A

34

2

1

5

6

B

34

2

1

65

SC
SX

25

A

2

6

4

1

5

3

B

2

6

4

1

5

3

1 710 109

©

Scania CV AB 2001, Sweden

102 019

Contents

Introduction .................................................................................. 3

Key to compressed air diagram .................................................................................. 4

List of components .................................................................................. 7

Position configuration ................................................................................ 24

Contents

©

2

Scania CV AB 2001, Sweden

10:00-01

Introduction

The brake diagram manual complements the
compressed air diagrams and contains
information required to read and understand
them.

The booklet comprises a list of components with
information on the components in the
compressed air system. The information covers
the designation, description, function and
symbol of each of the components. An
illustration is also provided showing the actual
appearance of the component.

Finally, the booklet contains the position
configuration. The figure shows an example of
how the components can be located in a vehicle
with 6x4 A/B ABS (6-channel).

Introduction

10:00-01

©

Scania CV AB 2001, Sweden

3

Key to compressed air diagram

Key to compressed air diagram

The compressed air diagram consists of a
skeleton diagram with symbols for the various
components. It shows only how the various
components are connected to one another, not
where the components are located or how the
compressed air lines are routed in the chassis.
Pipe connections and joints are not displayed in
the diagram either.

Beside each symbol is a designation, which also
can be found in the list of components in this
booklet. If several components have the same
function, they have the same symbol but
different designations.

Example

The task of a safety valve is always to open if
the pressure in a circuit becomes too high. For
this reason, the symbol for safety valve in the
diagram is always the same. However, a valve
that opens at 14.3 bar has number 13, while one
that opens at 19 bar is designated as 35 (see
figure).

13

Safety valve

14,3 bar

35

Safety valve
19 bar

©

4

Scania CV AB 2001, Sweden

10:00-01

In certain cases, components are differentiated

0

65

0

104723

0

by placing a letter after the number, depending
on what they are used for.

Example

7c is the designation for the front circuit air tank
and 7d is the designation for the rear circuit air
tank (see figure).

Next to each line on the diagram is a marking in
the form of two or three letters, as well as
information on the diameter of the line. The line
marking indicates which circuit the line belongs
to, where it originates and where it runs to. The
marking can also be found on the line in the
vehicle.

7c

Key to compressed air diagram

7d

1

2

1

Example

The designation MADØ16 indicates a line
belonging to the supply circuit running from the
compressor to the cooling coil. This has a
diameter of 16 mm. These markings are
explained in more detail in booklet 10:02-08,
Marking of compressed air lines and
connections.

Optional equipment is drawn in a box with
broken lines on the diagrams.

Components that constitute a single unit are
drawn in a dashed and dotted frame.

MAD

16

4 724
1

10:00-01

4 727
1

©

Scania CV AB 2001, Sweden

5

0

30

Key to compressed air diagram

The air connections indicated on the symbols
are marked with a number describing what each
connection is intended for. The designation for
Intake is normally 1. If there are two intakes,
they are designated 11 and 12. Outlet is
normally designated 2; if there are several they
receive the numbers 21, 22, 23 etc. Number 3 is
a vent and 4 a connection for control air.

4

22

1

21

3

10_2679

Air dryer

1 Intake

21 Outlet to four-circuit protection valve

22 Outlet to regeneration air tank

Electrical cable

The symbol shows that the component has an
electrical function.

3 Vent port

4 Control air to compressor.

4 7
1

©

6

Scania CV AB 2001, Sweden

10:00-01

10:00-01

9

0

653

0

3

List of components

Compressed air lines

Designation Symbol Function

Supply pipe Under normal operating conditions, conveys full supply pressure. The pipe

104 728

can be made of plastic or steel.§

©

Scania CV AB 2001, Sweden

Control pipe Under normal operating conditions, conveys a variable control pressure. The

4 72

pipe can be made of plastic or steel.

Flexible pipe The pipe consists of a rubber hose. A coiled hose is used for the trailer

connection.

2

1

Cooling coil The cooling coil consists of a steel pipe wound in a spiral. It is located after

the compressor and its function is to cool the compressed air.

10_2654

Joined pipes

1

4 7
1

Intersecting pipes

104 732

List of components

7

8

0

656

0

65

List of components

Components

No. Designation Symbol Function Illustration

©

Scania CV AB 2001, Sweden

3 Compressor

4

7

Brake chamber The brake chamber applies the force

Brake system air
tank

• 7b parking

• 7c front circuit

• 7d rear circuit

0

The compressor compresses air for
various compressed air systems.

2

4

• 0 Intake

• 2 Outlet

10 2655

• 4 control air to the compressor
relief valve.

10_2688

of the compressed air to the service
brake.

11

2

1

10_2689

The air tank holds a supply of
compressed air for the various

7

compressed air circuits.

2

1

105938

10:00-01

• 7k air dryer

10:00-01

10 2659

No. Designation Symbol Function Illustration

©

Scania CV AB 2001, Sweden

10 Low pressure

indicator

• 10a parking and
trailer brake
supply pressure
(5 bar)

The low pressure indicator is an
electrical monitor that closes if the
pressure drops below a certain value.
It is connected to a buzzer and a
warning lamp to warn if the air

10_2658

pressure is too low.

• 10b parking
brake control
pressure (6 bar)

12 Service brake valve The service brake valve is actuated by

the brake pedal and releases operating
air to the brake control system.

The safety valve opens when the
pressure exceeds a set value in order

13 Safety valve,

14,3 bar

11

12

21

22

to protect the system from
overpressure.

10 2690

b105775

10_2660

List of components

9

10

_

102 091

0

663

05

89

List of components

No. Designation Symbol Function Illustration

©

Scania CV AB 2001, Sweden

16 Pressure sensor with

monitor

The pressure sensor, which is an
electrical sensor, is connected to an
indicator enabling the pressure in the

P

P

supply pipes for the service brake
circuits to be read off. The monitor,
which closes when the pressure drops
below a certain value (5 bar), is
connected to a warning lamp and a

102661

buzzer to warn if the air pressure is
too low.

17 Brake lamp switch The brake lamp switch is

mechanically actuated and closes
when the brake pedal is depressed,
lighting the brake lights.

104 819

18 Quick release valve The quick release valve is used for

2

1

2

rapid draining of the parking circuit
pressure and for applying the parking
brake.

2691

10

10:00-01

2

1

1

1

10:00-01

_

No. Designation Symbol Function Illustration

©

Scania CV AB 2001, Sweden

19 Relay valve

• 19 rear circuit

• 19a is fitted on

certain vehicles
with tag axle and
TC

• 19b parking
circuit

• 19c front circuit

• 19d rear circuit

2

4

The relay valve is a compressed-air
controlled valve directly connected to

1

the supply pressure and directs this
proportionally in relation to the

2

control signal (4).

2664

10

• 19 is used for quicker application

10_2694

and release of the wheel brakes.

• 19a acts as a switch control valve,
preventing braking of the tag axle
during TC control.

• 19b is integrated with a check
valve. The purpose of the check
valve is to prevent the parking
brake being applied if there is no
pressure in the tank for the
parking and trailer circuits.

• 19c is used in vehicles with
double front axles. It has a quick
release function.

11

• 19d has an opening pressure of

0.42 bar.

List of components

12

0

665

06

05

10 2667

06

5

List of components

No. Designation Symbol Function Illustration

©

Scania CV AB 2001, Sweden

20d Trailer brake manual

control valve

1

21

3

Used to apply the trailer brake
separately. The valve has a micro
switch that closes when the valve is
actuated, lighting the brake lights.

2
1

23 Double check valve The double check valve opens for the

2

supply air connection with the highest
pressure.

1

25 Trailer brake

coupling

1

10_2666

The trailer brake couplings connect
the vehicle and trailer control and
supply lines for the trailer brake

10 2653

circuit.

105 890

2
1

10:00-01

26 Indicator An electrically controlled instrument

showing the pressure in the front and
rear circuits.

106206

6

0

10

0

1

6

10

77

2

1

106207

10:00-01

0

669

No. Designation Symbol Function Illustration

©

Scania CV AB 2001, Sweden

27 Spring brake

chamber

1211

28 Parking circuit

pressurizing valve

The spring brake chamber has a
compression spring for applying the
parking brake. The brake is released
by compressed air.

10_2668

Used to pressurize the parking circuit
and so release the parking brake.

2

1

32 Drain valve The drain valve is located at the

bottom of the air tanks and is used for
draining the tanks.

10_2670

35 Safety valve, 19 bar The purpose of the safety valve is to

protect the compressor against
overload by opening when the
pressure exceeds the set value.

13

10_2660

List of components

14

10 2657

0

6

List of components

No. Designation Symbol Function Illustration

©

Scania CV AB 2001, Sweden

36 Air suspension load

handling tank

The air tank is a store of compressed
air for vehicles with air suspension
and load handling.

39 Overflow valve The overflow valve is used on

1

vehicles with extra air tanks for load
handling.
The purpose is to protect the brake
system if the pressure drops in the

2

load handling tanks, and to supply the

72
2

1

brake system with air before the load
handling tanks are filled.

49 Load-sensing valve,

type 1, for vehicles
with leaf spring
suspension

1

2

The load sensing valve controls the
brake pressure to the rear circuit. It is
controlled by an outer arm. A heavy
load yields a high brake pressure and
a light load yields a lower brake
pressure to the rear axle.

10_2673

105938

10_2698

b106150

10:00-01

49 Load-sensing valve,

type 2, for vehicles
with air suspension

The load sensing valve controls the

1

2

brake pressure to the rear circuit. It is
controlled by the bellows pressure of
the drive shaft. A heavy load yields a
high brake pressure and a light load
yields a low brake pressure to the rear

4

106184

axle.

b106151

10:00-01

0

6

No. Designation Symbol Function Illustration

©

Scania CV AB 2001, Sweden

49 Load-sensing valve,

type 3, for vehicles
with air and leaf
spring suspension

1

The load sensing valve controls the
brake pressure to the rear circuit.

2

• Vehicle with leaf spring
suspension: The brake pressure to
the rear circuit is controlled by an
outer arm.

10_2673

• Vehicle with air suspension: The
brake pressure to the rear circuit
is controlled by the bellows

1

2

pressure of the drive shaft.

A heavy load yields a high brake
pressure and a light load yields a low
brake pressure to the rear axle.

4

106184

51 ABS control valve The control valve regulates the

pressure to the brake chambers, so
preventing wheel locking.

1

2

The control valve is also used for TC
control.

74
2

1

15

102 010

116 999

List of components

16

06

3

0

669

102011

©

Scania CV AB 2001, Sweden

No. Designation Symbol Function Illustration

52 Interlock valve The interlock valve closes when the

pressure drops below a certain value
and can then only be opened manually

1

2

when the system is pressurized again.
The purpose of the interlock valve is
to prevent release of the parking

10_2675

brake, which occurs if the parking
brake valve is in the released position
when charging up the pressure in the
brake system.

55 Test connection/

Pressurizing valve

A manometer can be connected to a
test connection to check the pressure
in a brake circuit.
To charge the compressed air system
from another compressed air source,
only the outlet by the footstep for the

2

driver area may be used. This is

1

located between the compressor and
the air dryer, so that the air passes
through the air dryer before reaching
components sensitive to moisture.

List of components

24

1

10:00-01

10:00-01

10 2676

0

6

0

03

No. Designation Symbol Function Illustration

©

Scania CV AB 2001, Sweden

57 Trailer relay valve The relay valve is a compressed air

22

12

controlled valve connected to the
parking/trailer circuit supply pressure.

11

The control pressure to the trailer is
directed in proportion to the control
signals from the front and rear brake
circuit as well as from the parking

43 42

41

brake or trailer brake manual control
valve.
The relay valve is used for quicker
application and release of the trailer
wheel brakes.

• 11 supply from tank.

• 12 supply to trailer.

• 22 operating air to trailer.

• 41 operating air from rear circuit.

• 42 operating air from front

circuit.

• 43 operating air from parking/
trailer circuit.

58 Pressure limiting

valve

• 58a exhaust
brake

• 58b parking/

1

• 58a limits the pressure to the

2

77
2

1

vehicle exhaust brake to 6.5 bar.

• 58b limits the pressure to the
vehicle trailer brake and parking
circuit to 8.0 bar.

trailer circuit

• 58c is used on vehicles with air

• 58c supply

circuit

suspension at a pressure of 12.2
bar in order to limit the pressure
for the brake system to 9.3 bar.

106200

List of components

27
1

17

18

List of components

No. Designation Symbol Function Illustration

©

Scania CV AB 2001, Sweden

59 Supply dump valve,

USA-adapted brake
system on
T124GA6x4 in
Mexico.

60 Four-circuit

protection valve

61d Parking brake

manual control valve

The supply dump valve for the trailer
supply air is connected to the parking
and trailer brake circuits. Together
with the manual control valve 61d,
without test position, the supply dump
valve ensures trailer parking brake
operation with the lever in parking
position.

21

1

22

23

24

The valve supplies four circuits with
compressed air. If the pressure drops
in any circuit (e.g. a ruptured line) the
four-circuit protection valve protects
the remaining circuits from

10 2678

depressurising. It also prioritises the
air supply to the service brake circuits
and accessories over the parking/
trailer circuit.

10_2704

Used to release the pressure in the
parking circuit and so apply the

1

21

parking brake. It can also be used as
an emergency brake.

22

10 2681

3

With or without test position.

10:00-01

103 450

10:00-01

0

8

8

102 014

10 2683

0

009

09

8

0

No. Designation Symbol Function Illustration

65 Manifold fitting Used as a manifold on a compressed

airline to distribute air to several
components.
Note: A manifold fitting may vary
widely in design, of which the

1
4
1

illustration shows an example.

©

Scania CV AB 2001, Sweden

66 Pressure reduction

valve

66a Pressure reduction

valve/front circuit.

4

with a single bogie and 4-channel
ABS. It reduces the brake pressure to
the tag axle brake chambers by 50%
during ABS control.

The valve is only used on vehicles

1

2

2
1

The valve reduces the pressure to the
front axle on tractors with an axle
distance of 3.3-3.7 m. The reduction

2

1

is only active if no trailer is coupled.

117 781

1

1

List of components

19

20

10 2685

List of components

No. Designation Symbol Function Illustration

©

Scania CV AB 2001, Sweden

74 Air dryer with

integrated pressure
regulator

79 Brake protection

valve

The air dryer removes moisture from

4

the air in order to prevent freezing and
other operating malfunctions.

22

1

3

• 1 Intake

21

• 21 outlet to four-circuit protection
valve.

10_2679

• 22 outlet to regeneration tank (air
tank 7k).

b106149

106 117

• 3 Venting

• 4 control air to compressor.

The brake protection valve ensures

2

1

that the rear circuit on vehicles with
air suspension with a load-sensing

3

valve receive full brake pressure if an
air bellows on the drive shaft is
punctured.

• 1 intake from rear circuit supply

10_2706

section.

• 2 connection from drive shaft air
suspension bellows.

10:00-01

• 3 control air to load-sensing
valve.

10:00-01

10 2680

6

No. Designation Symbol Function Illustration

©

Scania CV AB 2001, Sweden

81
81b
82
83

Solenoid valve Electromagnetic valve for controlling

1

2

compressed air.
81 is used for TC control and is
normally closed.
81b is used to release the parking
brake on the front axle during ELC
control. The valve is normally closed.
82 is used together with 66 to reduce
the pressure on the tag axle during
ABS control (only vehicles with
single bogie and 4-channel ABS). The
valve is normally open.
83 is used together with 58a for the
exhaust brake and is normally closed.

84 Buzzer The buzzer sounds if the air pressure

in the front, rear or parking/trailer
circuit becomes too low.

10 2684

102 012

21

86 Pressure sensor, EBS The pressure sensor measures the

pressure in the drive shaft air bellows.
The control unit uses this value
together with the value from the
service brake valve in order to
calculate which brake pressure value
is to be activated from the control
modules.

List of components

4

114 1

22

105778

©

Scania CV AB 2001, Sweden

No. Designation Symbol Function Illustration

92 Trailer control

module, EBS

1

21

The trailer control module ensures

41

that the control pressure to the trailer

43

is correct. It also balances the

42

pressure so that the brake adaptation

0

between the trailer and the vehicle is

8
7

22

93 Emergency brake

valve, USA-adapted
brake system.

7
1
1

correct.

The emergency brake valve ensures
braking of the rear wheels via the
spring brake if the rear circuit is
depressurised.

List of components

114 082

10:00-01

94 Control module,

single EBS

14

2

The EBS control unit measures the
driver's required braking power and
sends this information to the control
modules. These then direct air to the
brake chambers. EBS also controls
ABS and TC control of the brakes.
The control module has an emergency
brake function that is engaged if the
electronics fail.

105 221

10:00-01

050

0

9

No. Designation Symbol Function Illustration

©

Scania CV AB 2001, Sweden

95 Control module,

double EBS

4

1

The EBS control unit measures the
driver's required braking power and
sends this information to the double
control module. This then directs air
to the brake chambers. EBS also
controls ABS and TC control of the

21

22

brakes.

117

The control module has an emergency
brake function that is engaged if the
electronics fail. The double control
module controls the braking of two or

7

114

four wheels.

23

List of components

24

1

9

105 904

Position configuration

6x4 A/B ABS (6-channel)

©

Scania CV AB 2001, Sweden

26

12
17

35

10b

61d

52

20d

28

84

36

39

58a

18

83

51

27

19,23

51

79

18

51

81

65

25

5

4

10:00-01

55

65

3

10a

16

7k

65

55

60
58c

13

74

4

23

19b

55

65

7b

32 7c

7d

57

58b

10:00-01

©

Scania CV AB 2001, Sweden

3 Compressor
4 Brake chamber 51 ABS control valve
7b Air tank, parking/trailer circuit 52 Interlock valve
7c Air tank, front circuit 55 Test connection/Pressurizing valve
7d Air tank, rear circuit 57 Trailer relay valve
7k Air tank, air dryer 58a Pressure limiting valve, exhaust brake
10a Supply pressure low pressure indicator, parking circuit 58b Pressure limiting valve, parking/trailer circuit
10b Control pressure low pressure indicator, parking circuit 58c Pressure limiting valve, vehicle with air suspension
12 Service brake valve 60 Four-circuit protection valve
13 Safety valve, 14,3 bar 61d Manual control valve, parking circuit
16 Pressure sensor with monitor, front/rear circuit 65 Manifold fitting
17 Brake lamp switch 74 Air dryer with integrated pressure regulator
18 Quick release valve 79 Brake protection valve
19 Relay valve, rear circuit 81 Solenoid valve, TC
19b Relay valve, parking circuit 83 Solenoid valve, exhaust brake
20d Manual control valve, trailer circuit 84 Buzzer
23 Double check valve

25

25 Trailer brake connection
26 Pressure indicator, front/rear circuit
27 Spring brake chamber
28 Pressurizing valve, parking circuit
32 Drain valve
35 Safety valve, 19 bar
36 Air tank, air suspension
39 Overflow valve
49 Load-sensing valve

Position configuration