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Home >> Audi >> 2021 >> TT Quattro Base, 2D Convertible >> Repair and Diagnosis >> Brakes >> Traction Control >> Antilock Brake System [Roadster] >> 45 Antilock Brake System >> Control Module And Hydraulic Unit >> ABS Control Module -J104- /ABS Hydraulic Unit -N55-, REMOVING AND INSTALLING >> ABS Control Module -J104- AND ABS Hydraulic Unit -N55-, REMOVING AND INSTALLING, VEHICLES WITH A TDI ENGINE >> Installing
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ABS Control Module -J104- AND ABS Hydraulic Unit -N55-, REMOVING AND INSTALLING, VEHICLES WITH A TDI ENGINE: Installing

Install in reverse order of removal and note the following:

-- Place the hydraulic control module on the subframe.

-- Install the mounting bracket for the hydraulic control module in the vehicle.

-- Push the hydraulic control module -1- with the bracket into the pins in the engine compartment -arrows-.

GWWA45-10183Courtesy of AUDI OF AMERICA, LLC
NOTE:

The hydraulic control module must rest in all pins.

Only remove the plugs on the new hydraulic unit if the corresponding brake line is installed.

If the plugs are removed too early from the hydraulic unit, brake fluid can escape and the unit may not be sufficiently filled or adequately bled.

When installing the hydraulic control module, make sure the rubber buffer is not pushed out of the bracket.

Identification of the hydraulic unit.

Fig 1: Hydraulic Unit Brake Line Installation Sequence
GWWN45-10244Courtesy of AUDI OF AMERICA, LLC

A -  Hydraulic Unit To Master Brake Cylinder Primary Piston Circuit -HZ2-

B -  Hydraulic Unit To Master Cylinder Secondary Piston Circuit -HZ1-

1 -  Hydraulic Unit To Right Rear Brake Caliper -HR-

2 -  Hydraulic Unit To Left Front Brake Caliper -VL-

3 -  Hydraulic Unit To Right Front Brake Caliper -VR-

4 -  Hydraulic Unit To Left Rear Brake Caliper -HL-

WARNING:
  • Do not damage the brake hose and brake line.
  • Do not bend the brake line past the specified form.
  • A damaged brake hose or a damaged or bent brake line must be replaced.

-- Insert all brake lines into the ABS Hydraulic Unit -N55-, install all union bolts by hand and tighten in the sequence -1 through 6-.

Fig 2: Brake Lines, Attaching To Hydraulic Unit Sequence
GWWN45-10263Courtesy of AUDI OF AMERICA, LLC

-- Remove the : VAG1869/2  .

-- HYDRAULIC SYSTEM, BLEEDING .

-- Install the front exhaust pipe. Refer to OVERVIEW - MUFFLER .

-- Install the engine cover. Refer to ENGINE COVER, REMOVING AND INSTALLING .

-- If the ABS Control Module -J104- /ABS Hydraulic Unit -N55- is being replaced, select the "Replace" function for the ABS Control Module -J104- /ABS Hydraulic Unit -N55- on the Vehicle Diagnostic Tester, Guided Functions  .

WARNING:

Risk of accident!

  • Make sure the brakes are working correctly before driving the vehicle for the first time.