ABS Mark 70 (ABS/ASR)

Master Cylinder and Brake Booster Assembly Overview





1 Anti-lock Brake System (ABS) control module (w/Electronic Differential Lock (EDL) (J104)

• Removing and installing, refer to --> [ Control Module and Hydraulic Unit ] Service and Repair.

2 ABS hydraulic unit (N55)

• Removing and installing, refer to --> [ Control Module and Hydraulic Unit ] Service and Repair.

3 Brake line

• Tightening specification: 14 Nm.

• Master cylinder/primary piston circuit to hydraulic control unit.

• Identification: Fitting with either M10 x 1 or M12 x 1 threads.

CAUTION!
During production, the fitting threads were changed from M10 x 1 to M12 x 1.

4 Brake line

• Tightening specification: 14 Nm.

• Master cylinder/secondary piston circuit to hydraulic control unit.

• Identification: Fitting with M12 x 1 threads.

5 Brake line

• Tightening specification: 14 Nm.

• To the left front brake caliper.

• Identification: Fitting with either M10 x 1 or M12 x 1 threads.

CAUTION!
During production, the fitting threads were changed from M10 x 1 to M12 x 1.

6 Brake line

• Tightening specification: 14 Nm.

• To the right front brake caliper.

• Identification: Fitting with either M10 x 1 or M12 x 1 threads.

CAUTION!
During production, the fitting threads were changed from M10 x 1 to M12 x 1.

7 Brake line

• Tightening specification: 14 Nm.

• To the left rear brake caliper.

• Identification: Fitting with M12 x 1 threads.

8 Brake line

• Tightening specification: 14 Nm.

• To the right rear brake caliper.

• Identification: Fitting with M10 x 1 threads.

9 Torx bolt, 5.5 Nm

• Use new bolts.

10 Bracket

11 Bolt, 8 Nm

12 Gasket

• For the brake booster.

13 Brake booster

• On gas engines, vacuum is supplied from the intake manifold.

• On diesel engines, a vacuum pump is installed for vacuum creation. Refer to --> [ Brake Booster Vacuum Pump Overview ] Brake Booster Vacuum Pump Overview.

• Functional test:

- Forcefully press brake pedal several times with the engine off. This dissipates any vacuum present in the unit.

- Press and hold the brake pedal with average foot pressure and start the engine. If the brake booster is working properly, the pedal will be felt to give noticeably under foot (booster assistance becomes effective).

• If malfunctioning: replace the booster as a complete unit.

• Removing and installing, refer to --> [ Brake Booster ] Brake Booster.

14 Seal

15 Dual master cylinder

• Cannot be serviced. Replace as complete unit if malfunctioning.

• Removing and installing, refer to --> [ Master Cylinder ] Master Cylinder.

16 Nut, 25 Nm

• Always replace after removal.

17 Sealing plugs

• Lubricate with brake fluid and press into the brake fluid reservoir.

18 Brake fluid reservoir

19 Cap

20 Sealing plugs

• Connection for vacuum hose.

21 Vacuum hose

• Insert into the brake booster.

22 Brake booster pressure sensor (G294)

• On vehicles with a Fuel Straight Injection (FSI) engine without hydraulic brake vacuum booster.

• Removing and installing, refer to --> [ Brake Booster Pressure Sensor ] Brake Booster Pressure Sensor.