lock AUDI A4 1997 B5 / 1.G ABS Bosch 5.3 Workshop Manual
[x] Cancel search | Manufacturer: AUDI, Model Year: 1997, Model line: A4, Model: AUDI A4 1997 B5 / 1.GPages: 6, PDF Size: 0.11 MB
Page 1 of 6

45-18
 
     
Anti-lock Brake System (ABS), 
Bosch 5.3 
      A traction control system (TCS/ASR) is available 
as optional equipment for front-wheel-drive 
models.  
      The brake system of the ABS is split diagonally. 
The brake servo assistance is provided 
pneumatically by a vacuum brake servo unit.  
    
Hydraulic unit -a- and ABS control module -b- form a single unit. The 
combination of these two components is termed the hydraulic control 
unit.  
Sources of malfunctions are reduced as a result of the direct link between 
the two components.  
CAUTION! 
It is not possible to repair the hydraulic control unit. If faulty, it 
should be replaced. The bolts which connect the individual components of the 
hydraulic control unit must not be loosened. 
Pa
ge 1 of 6 Anti-lock Brake S
ystem 
(ABS
), Bosch 5.3
11/19/2002 htt
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play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.SU03.45.3 
Page 2 of 6

45-19
 
  
ABS hydraulic control unit and brake lines
 
The tightening torque for all brake lines on the Audi 
A4 is 15 Nm (11 ft lb).  
1 - 
Brake master cylinder and brake servo 
2 - 
Brake line 
Brake master cylinder/primary piston circuit 
to hydraulic control unit 
3 - 
Brake line Brake master cylinder/secondary piston 
circuit to hydraulic control unit 
4 - 
Brake line Hydraulic control unit to left-front brake 
caliper 
5 - 
Brake line Hydraulic control unit to right-front brake 
caliper 
Pa
ge 2 of 6 Anti-lock Brake S
ystem 
(ABS
), Bosch 5.3
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.SU03.45.3 
Page 3 of 6

45-20
 
  
6 - 
Suction dampers 
Designed to improve pressure build-up 
during operation of EDL Discontinued; phased in integration into 
hydraulic control unit 
7 - 
Brake line Hydraulic control unit to left-rear brake 
caliper 
8 - 
Brake line Hydraulic control unit to right-rear brake 
caliper 
9 - 
Nut 10 Nm (7 ft lb)
10 - 
Bolt 10 Nm (7 ft lb)
11 - 
Bracket 
Pa
ge 3 of 6 Anti-lock Brake S
ystem 
(ABS
), Bosch 5.3
11/19/2002 htt
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play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.SU03.45.3 
Page 4 of 6

45-21
      
ABS hydraulic control unit, removing 
and installing 
 
     
Note:  
     When working with brake fluid, observe the 
relevant safety precautions and notes   Brake 
system, bleeding, page 47
-23
 . 
     
Special tools and equipment  
     
Sealing plugs from repair kit Part No. 1H0 698 
311A 
     Brake pedal depressor, e.g. from VAG1813
     
CAUTION! 
     
Part numbers are listed here for reference 
only. Always check with your Parts 
department for the latest information. 
      Component location:  
    
The hydraulic control unit is installed on the left side of the engine 
compartment.  
Pa
ge 4 of 6 Anti-lock Brake S
ystem 
(ABS
), Bosch 5.3
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.SU03.45.3 
Page 5 of 6

45-22
      
Removing  
     
CAUTION! 
     
Do not bend the brake lines.
     Before disconnecting the battery, determine 
the correct coding for the anti-theft radio. 
     
-  Disconnect battery Ground (GND) strap.
    
Note:  
The brake pedal depressor must remain in position until all of the brake 
lines have been reconnected to the hydraulic control unit.  -  Release control unit connector (arrow -1-) and disconnect harness 
connector (arrow -2-). 
-  Connect bleeder bottle to bleeder screw on left-front brake caliper and 
open bleeder screw. 
-  Install brake pedal depressor between brake pedal and driver's seat. 
Depress brake pedal by at least 60 mm (2 3/8 in.). 
-  Close left-front bleeder screw.
-  Cover engine compartment to make sure brake fluid does not flow into 
it. 
-  Disconnect brake line connections on hydraulic control unit.
Pa
ge 5 of 6 Anti-lock Brake S
ystem 
(ABS
), Bosch 5.3
11/19/2002 htt
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play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.SU03.45.3 
Page 6 of 6

45-23
      
-  Seal brake lines and threaded holes using plugs 
from repair kit, Part No. 1H0 698 311 A. 
     
-  Remove nuts from ABS hydraulic control unit 
bracket. 
     
-  Remove ABS hydraulic control unit.
     
Installing  
     
Note:  
     When installing, pay particular attention to the 
following points. 
     
Only remove the sealing plugs on the new 
hydraulic control unit when the corresponding 
brake line is about to be installed. 
     If the sealing plugs are removed too early the 
brake fluid can escape. If this occurs, the unit 
will no longer be sufficiently filled or adequately 
bled. 
     
-  Bleed brake system   page 47
-23
 .
     
- Enter radio code.
Pa
ge 6 of 6 Anti-lock Brake S
ystem 
(ABS
), Bosch 5.3
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.SU03.45.3