Antilock Brakes / Traction Control Systems: Service and Repair

Hydraulic Unit Assembly Overview, ABS MK 25






1 ABS Control Module (w/EDL) (J104)

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

2 ABS Hydraulic Unit (N55)

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

3 Bolt

• 2 + 0.8 Nm

• Tighten diagonally, in steps, without tilting it.

4 Bracket

• Allocation, refer to the Electronic Parts Catalog (ETKA).

5 Bolt

• 9 Nm

6 Rubber Insulation

7 Brake Line

• 18 Nm

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

• Identification: 8.5 mm and tube fitting with M12 x 1 thread.

8 Brake Line

• 18 Nm

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

• Identification: 8.5 mm and tube fitting with M12 x 1 thread.

9 Brake Booster with Master Brake Cylinder

• Assembly overview, refer to => [ Brake Booster/Brake Master Cylinder Overview ] Brake Booster/Brake Master Cylinder Overview.

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

10 Brake Line

• 14 Nm

• To left rear brake caliper.

• Identification: 5.25 mm and tube fitting with M12 x 1 thread.

11 Brake Line

• 14 Nm

• To right front brake caliper.

• Identification: Diameter 5.25 mm and tube fitting with M10 x 1 thread.

12 Brake Line

• 14 Nm

• To left front brake caliper.

• Identification: 5.25 mm and tube fitting with M12 x 1 thread.

13 Brake Line

• 14 Nm

• To right rear brake caliper.

• Identification: Diameter 5.25 mm and tube fitting with M10 x 1 thread.

Brake Lines from Brake Master Cylinder, Connecting to Hydraulic Unit

On the Brake Master Cylinder







On Hydraulic Unit





A Hydraulic unit to primary piston circuit of master brake cylinder.
Identification: 8.5 mm and tube fitting with M12 x 1 thread.
B Hydraulic unit to master cylinder secondary piston circuit.
Identification: 8.5 mm and tube fitting with M12 x 1 thread.
1 Hydraulic control unit to rear left brake caliper.
Identification: 5.25 mm and tube fitting with M12 x 1 thread.
2 Hydraulic unit to right front brake caliper.
Identification: Diameter 5.25 mm and tube fitting with M10 x 1 thread.
3 Hydraulic unit to front left brake caliper.
Identification: 5.25 mm and tube fitting with M12 x 1 thread.
4 Hydraulic control unit to rear right brake caliper.
Identification: Diameter 5.25 mm and tube fitting with M10 x 1 thread.