Overview - Brake Booster/Brake Master Cylinder, Electromechanical Brake Booster

Fig 1: Exploded View Of Brake Booster/Brake Master Cylinder (Electromechanical Brake Booster)

Courtesy of AUDI OF AMERICA, LLC

1. Brake Line
   • 14 Nm
   • Brake master cylinder/primary piston circuit to hydraulic unit
2. Brake Line
   • 14 Nm
   • To the Brake System Pressure Reservoir -VX70-
3. Master Brake Cylinder
   • Cannot be serviced. If malfunctioning, replace as complete unit.
   • Refer to BRAKE MASTER CYLINDER, REMOVING AND INSTALLING, WITH ELECTROMECHANICAL BRAKE MASTER CYLINDER 
4. Seal
   • Replace after removing.
5. Plugs
   • To install, coat with brake fluid
6. Bolt
   • 4 Nm
     CAUTION:

     Clean the bolts and nuts before reusing.

     Replace the bolts and nuts if damaged.

     Replace the self-locking bolts and nuts after removing

7. Brake Fluid Reservoir
   • Refer to BRAKE FLUID RESERVOIR, REMOVING AND INSTALLING 
8. Cap
9. Brake Fluid Level Warning Switch -F34-
   • Refer to Brake Fluid Level Warning Switch -F34-, REMOVING AND INSTALLING 
10. Protective Plate
    • Equipped on some models
      CAUTION:

      The protective plate is only installed depending on the model.

11. Rubber Buffer
12. Bolt
    • 8 Nm
      CAUTION:

      Clean the bolts and nuts before reusing.

      Replace the bolts and nuts if damaged.

      Replace the self-locking bolts and nuts after removing

13. Seal
    • Replace after removing.
14. Brake Booster Control Module -J539-
    • With integrated Brake Pedal Position Sensor -G100-
      CAUTION:

      Deformation increases the risk of damage.

      - Do not hold the brake booster on the actuator rod.

    • Refer to BRAKE BOOSTER, REMOVING AND INSTALLING, ELECTROMECHANICAL BRAKE BOOSTER 
15. Bolt
    • 25 Nm
      CAUTION:

      Clean the bolts and nuts before reusing.

      Replace the bolts and nuts if damaged.

      Replace the self-locking bolts and nuts after removing

16. Bolt
    • 22 Nm
    • Replace after removing.
17. Brake Line
    • 14 Nm
    • Brake master cylinder/secondary piston circuit to hydraulic unit

Brake Booster Ball Head, Adjusting

Fig 2: Brake Booster Ball Head, Adjusting

Courtesy of AUDI OF AMERICA, LLC

• Dimension -a- = 167 mm ± 0.5 mm
• When measuring, the ball head must be aligned at a right angle to the brake booster surface.
• Measure to end of ball head without the seal.

Tightening Specification