10:00-01

Issue 2 en

Brake Diagram Manual

B6 SK 6
27
35 4

27 MAD 16 3
55
11 12

55 XCJ 12

SJ 6

16
MP 6 FB 12 BCK 12
11 12 MK 6 1 49

MA
MV 16 MAM 6 51
1 2
4
28 52

PCD 12
4 1 2
61d 74 27

4
58a

12
PG 6 22

PZ 12 B2 MU 8 1 7k 4
21 83 55

8
FAV

PF 12
BYC 6
1

7d 2

BL
2

10b PH 6 B1 55 13 PK 6 3
79 51
65

6
PE 8 B5 PC 8 32 1
19 18

PCC
12
BAF 12

BYB
BC 12
17 BAG 12

PD 12
12 FBC 12 FBS 12 51

16
FAG 12 7d 2

21 11 FA 12
16 22 55

MAO

12
PX
12

BCC 6 1 2 32 BYD 8 55
FAF 12 51 7c
FBO 6 4
22
21 11 12 27 32 27
23
1 24
4 BCL 12
58c 19
16 XCF 12 XCE 12
65 BA 12
B3 SC
84 Opt. SX 25
10a PA 12

XM 12
55 PO 6

BCG 8 B3 BK 8
BCF 12 A3 BAG 5
55 PBX 12 B4 PCF
12
12 A 6
PBU 6 A2 PO 6
PBW 12 B6 PCB 12 3 4 A 6 2
36 36 36 36 Opt.
19b 1 2 4
32 32 32 57 58b 7b
22 12
21 1
1 PBV 12 A1 PA 12 5 1
39 2

MBK 12 MBJ 12 MBH 12

2 11
32 3
55 PBZ 12
SAU 8

42 41 4 22
8 8
43 PBS A5 PC
B B
SAV 8

2 5 6 6 2
11 12 PBT 6 A4 PK 6
55 23 FBR 8 B5 FBS 8 4
SAP 6 A6 SK 6
3 4 5 1
55 SAR 6 B2 SX 12
SAS 12 B1 SC 12 3
1 2
Middle valve unit

102 019

© Scania CV AB 2001, Sweden

1 710 109
Contents

Contents
Introduction .................................................................................. 3

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

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

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

© Scania CV AB 2001, Sweden

2 10:00-01
 Introduction

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).

© Scania CV AB 2001, Sweden

10:00-01 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
13 35
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 Safety valve Safety valve
diagram is always the same. However, a valve 14,3 bar 19 bar
that opens at 14.3 bar has number 13, while one
that opens at 19 bar is designated as 35 (see
figure).

© Scania CV AB 2001, Sweden

4 10:00-01
 Key to compressed air diagram

In certain cases, components are differentiated

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 7c 7d
tank (see figure).

10 2651
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.
Example

The designation MADØ16 indicates a line MAD 16

belonging to the supply circuit running from the
compressor to the cooling coil. This has a

104 724
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.
104 723
104 727

© Scania CV AB 2001, Sweden

10:00-01 5
Key to compressed air diagram

The air connections indicated on the symbols

are marked with a number describing what each 4
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 22
receive the numbers 21, 22, 23 etc. Number 3 is
a vent and 4 a connection for control air. 1
21

10_2679
Air dryer
1 Intake
21 Outlet to four-circuit protection valve
22 Outlet to regeneration air tank
3 Vent port
4 Control air to compressor.

Electrical cable
The symbol shows that the component has an
electrical function.

104 730

© Scania CV AB 2001, Sweden

6 10:00-01
 List of components

10:00-01
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.§
Control pipe Under normal operating conditions, conveys a variable control pressure. The

04 729
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.

10 2653
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

© Scania CV AB 2001, Sweden

Joined pipes

104 731
Intersecting pipes

104 732
List of components

7
8
Components

No. Designation Symbol Function Illustration

List of components

3 Compressor 0 The compressor compresses air for

various compressed air systems.
2
• 0 Intake
• 2 Outlet
4

10 2655
• 4 control air to the compressor
relief valve.
10_2688

4 Brake chamber The brake chamber applies the force

of the compressed air to the service
brake.
11

© Scania CV AB 2001, Sweden

10 2656
10_2689

7 Brake system air The air tank holds a supply of

tank compressed air for the various
• 7b parking compressed air circuits.

10 2657
• 7c front circuit
105938

• 7d rear circuit
• 7k air dryer

10:00-01
 No. Designation Symbol Function Illustration
10 Low pressure The low pressure indicator is an
indicator electrical monitor that closes if the

10:00-01
• 10a parking and pressure drops below a certain value.
trailer brake It is connected to a buzzer and a
supply pressure warning lamp to warn if the air

10_2658
(5 bar) pressure is too low.
• 10b parking

10 2690
brake control
pressure (6 bar)
12 Service brake valve The service brake valve is actuated by
the brake pedal and releases operating
11 21
air to the brake control system.
b105775

12 22

10 2659
13 Safety valve, The safety valve opens when the
14,3 bar pressure exceeds a set value in order
to protect the system from

© Scania CV AB 2001, Sweden

overpressure.

10_2660
List of components

9
10
No. Designation Symbol Function Illustration
16 Pressure sensor with The pressure sensor, which is an
monitor electrical sensor, is connected to an
indicator enabling the pressure in the
List of components

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

10_2691
connected to a warning lamp and a
10 2661
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
102 091

© Scania CV AB 2001, Sweden

18 Quick release valve 2
The quick release valve is used for
1
rapid draining of the parking circuit
pressure and for applying the parking
2
brake.

10 2663
105 891

10:00-01
 No. Designation Symbol Function Illustration
19 Relay valve The relay valve is a compressed-air
2
• 19 rear circuit controlled valve directly connected to

10:00-01
4 1 the supply pressure and directs this
• 19a is fitted on proportionally in relation to the
certain vehicles
2 control signal (4).
with tag axle and

10_2664
• 19 is used for quicker application

10_2694
TC
and release of the wheel brakes.
• 19b parking
circuit • 19a acts as a switch control valve,
preventing braking of the tag axle
• 19c front circuit during TC control.

• 19d rear circuit • 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

© Scania CV AB 2001, Sweden

release function.
• 19d has an opening pressure of
0.42 bar.
List of components

11
12
No. Designation Symbol Function Illustration
20d Trailer brake manual Used to apply the trailer brake
control valve separately. The valve has a micro
1
switch that closes when the valve is
List of components

21 actuated, lighting the brake lights.

10 2665
3

23 Double check valve The double check valve opens for the
2 supply air connection with the highest
pressure.
1 1
106205

105 890

10_2666

© Scania CV AB 2001, Sweden

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

10 2653
circuit.
106206
106207

26 Indicator An electrically controlled instrument 6 6

0 10 0 10
showing the pressure in the front and
rear circuits.
1 2
106 775

10 2667

10:00-01
 No. Designation Symbol Function Illustration
27 Spring brake The spring brake chamber has a
chamber compression spring for applying the

10:00-01
11 12 parking brake. The brake is released

10_2668
by compressed air.

28 Parking circuit Used to pressurize the parking circuit

pressurizing valve and so release the parking brake.

106 244

10 2669
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

© Scania CV AB 2001, Sweden

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

10_2660
List of components

13
14
No. Designation Symbol Function Illustration
36 Air suspension load The air tank is a store of compressed
handling tank air for vehicles with air suspension
and load handling.

10 2657
List of components

105938
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

10 2672
brake system with air before the load
10_2698

handling tanks are filled.

49 Load-sensing valve, The load sensing valve controls the

type 1, for vehicles 1 2 brake pressure to the rear circuit. It is
with leaf spring controlled by an outer arm. A heavy

© Scania CV AB 2001, Sweden

suspension load yields a high brake pressure and
a light load yields a lower brake

10_2673
pressure to the rear axle.
b106150

49 Load-sensing valve, The load sensing valve controls the

type 2, for vehicles 1 2 brake pressure to the rear circuit. It is
with air suspension 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
 No. Designation Symbol Function Illustration
49 Load-sensing valve, The load sensing valve controls the
type 3, for vehicles brake pressure to the rear circuit.

10:00-01
1 2
with air and leaf • Vehicle with leaf spring
spring suspension 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

© Scania CV AB 2001, Sweden

control.

10 2674
102 010
116 999
List of components

15
16
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
List of components

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
106 243
when charging up the pressure in the
brake system.
55 Test connection/ A manometer can be connected to a
Pressurizing valve 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
driver area may be used. This is

10 2669
102 011

located between the compressor and

© Scania CV AB 2001, Sweden

the air dryer, so that the air passes
through the air dryer before reaching
components sensitive to moisture.

10:00-01
 No. Designation Symbol Function Illustration
57 Trailer relay valve 12
The relay valve is a compressed air
22 controlled valve connected to the

10:00-01
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
brake or trailer brake manual control

10 2676
41 43 42

106200
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.

© Scania CV AB 2001, Sweden

• 43 operating air from parking/
trailer circuit.
58 Pressure limiting • 58a limits the pressure to the
valve 2
vehicle exhaust brake to 6.5 bar.
1
• 58a exhaust
brake • 58b limits the pressure to the

10 2677
vehicle trailer brake and parking
• 58b parking/ circuit to 8.0 bar.
trailer circuit
• 58c is used on vehicles with air
• 58c supply suspension at a pressure of 12.2
10 2703

circuit bar in order to limit the pressure

for the brake system to 9.3 bar.
List of components

17
18
No. Designation Symbol Function Illustration
59 Supply dump valve, The supply dump valve for the trailer
USA-adapted brake supply air is connected to the parking
system on and trailer brake circuits. Together
List of components

T124GA6x4 in with the manual control valve 61d,

Mexico. without test position, the supply dump
valve ensures trailer parking brake
operation with the lever in parking
position.
60 Four-circuit 21
The valve supplies four circuits with
protection valve 22
compressed air. If the pressure drops
1
23 in any circuit (e.g. a ruptured line) the
24
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

© Scania CV AB 2001, Sweden

61d Parking brake Used to release the pressure in the
manual control valve parking circuit and so apply the
1 21 parking brake. It can also be used as
an emergency brake.
22

10 2681
With or without test position.
3
103 450

10:00-01
 No. Designation Symbol Function Illustration
102 014

65 Manifold fitting Used as a manifold on a compressed

airline to distribute air to several

10:00-01
components.
Note: A manifold fitting may vary
widely in design, of which the

104 818
illustration shows an example.

66 Pressure reduction The valve is only used on vehicles

4
valve with a single bogie and 4-channel
ABS. It reduces the brake pressure to
the tag axle brake chambers by 50%
during ABS control.
1 2

10 2683
102 009

66a Pressure reduction The valve reduces the pressure to the

valve/front circuit. 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.

© Scania CV AB 2001, Sweden

109 810

117 781
List of components

19
20
No. Designation Symbol Function Illustration
74 Air dryer with The air dryer removes moisture from
integrated pressure 4 the air in order to prevent freezing and
regulator other operating malfunctions.
22
List of components

• 1 Intake
1
21
• 21 outlet to four-circuit protection
3 valve.

10_2679
b106149
• 22 outlet to regeneration tank (air
106 117

tank 7k).
• 3 Venting
• 4 control air to compressor.
79 Brake protection The brake protection valve ensures
valve 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

10 2685

© Scania CV AB 2001, Sweden

punctured.
• 1 intake from rear circuit supply
10_2706

section.
• 2 connection from drive shaft air
suspension bellows.
• 3 control air to load-sensing
valve.

10:00-01
 No. Designation Symbol Function Illustration
81 Solenoid valve Electromagnetic valve for controlling
1
81b compressed air.

10:00-01
82 2 81 is used for TC control and is
83 normally closed.
81b is used to release the parking

10 2680
brake on the front axle during ELC
control. The valve is normally closed.
82 is used together with 66 to reduce

102 012
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

© Scania CV AB 2001, Sweden

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.
114 164
List of components

21
22
No. Designation Symbol Function Illustration
92 Trailer control 21 1 The trailer control module ensures
41
module, EBS 43
that the control pressure to the trailer
42
is correct. It also balances the
List of components

pressure so that the brake adaptation

22 between the trailer and the vehicle is

117 780
correct.

114 082
93 Emergency brake The emergency brake valve ensures
valve, USA-adapted braking of the rear wheels via the
brake system. spring brake if the rear circuit is
depressurised.

94 Control module, The EBS control unit measures the

1 4
single EBS driver's required braking power and

© Scania CV AB 2001, Sweden

sends this information to the control
2
modules. These then direct air to the

105778
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
 No. Designation Symbol Function Illustration
95 Control module, 1 4
The EBS control unit measures the
double EBS driver's required braking power and

10:00-01
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

117 050
brakes.
The control module has an emergency
brake function that is engaged if the
electronics fail. The double control 114 079

module controls the braking of two or

four wheels.

© Scania CV AB 2001, Sweden

List of components

23
24
6x4 A/B ABS (6-channel)

61d 20d 84
Position configuration

19,23 18
58a 18 51 51 79 81 65 25
26 10b 52 28 83
39
36
51
12 49
17

© Scania CV AB 2001, Sweden

27
35
51
7b 32 7c 7d
65 4
3 7k
55 65 23
10a 60
55 58c 57
16 19b
13
55
74
105 904

65 58b

10:00-01
 3 Compressor
4 Brake chamber 51 ABS control valve

10:00-01
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

© Scania CV AB 2001, Sweden

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

25