Brake systems · Brakes – hydraulics · Removing and installing brake booster

Removing and installing brake booster, left-hand drive

Special tools and workshop equipment required

7.1.1 Removing

Note or request radio code on vehicles with coded radio if necessary.
Disconnect battery. ⇒ Electrical system; Rep. gr. 27; Disconnecting and reconnecting battery.
Remove intake hose and air filter housing.
Remove engine control unit ⇒ Rep. gr. 24.
Remove bracket for engine control unit.

Unbolt fastening tab for air filter.
Disconnect connector -A- from brake fluid level warning contact - F34-.
Separate connector -C- from brake light switch - F-.
Place sufficient lint-free cloths in area of engine and gearbox.
Draw off as much brake fluid as possible from brake fluid reservoir using brake filling and bleeding equipment - VAS 5234- or extraction unit -V.A.G 1869/4-.

Additional work on following engines and gearboxes:

3-cyl. injection engine (4-valve):

Remove throttle valve module - J338- ⇒ 3-cyl. injection engine (4-valve); Rep. gr. 24; Injection system; Assembly overview
- intake manifold.

4-cyl. injection engine, toothed belt drive:

Removing and installing ⇒ Electrical system; Rep. gr. 27; Removing and installing battery

4-cylinder direct injection engines (2.0 l, 4 V, turbocharger, toothed belt drive):

Remove air filter housing -1- with air hose ⇒ Rep. gr. 24; Air filter; Removing and installing air filter housing.

Remove engine control unit -2-, and lay it to one side ⇒ Rep. gr. 23; Engine control unit; Removing and installing engine control unit.
Remove bracket for engine control unit from bulkhead.
Remove rear bracket for air filter housing ⇒ Rep. gr. 24; Air filter; Assembly overview - air filter housing.

4-cylinder injection engine (1.4 l and 1.6 l engine, BiFuel):

Remove natural gas vaporizer ⇒ Rep. gr. 24; Removing and installing vaporizer for vehicles with liquefied petroleum gas drive.

3-cylinder diesel engine (1.2 l engine, common rail):

Loosen charge air pipe and screw-type clip -1- on connecting hose leading to turbocharger ⇒ 3-cylinder diesel engine (1.2 l engine, common rail); Rep. gr. 21.

Then unbolt pulsation damper from turbocharger and remove along with connecting hose.

4-cylinder diesel engine (1.6 l engine, common rail):

Loosen charge air pipe and screw-type clip to turbocharger ⇒ 4-cylinder diesel engine (1.6 l engine, common rail); Rep. gr. 21.

Then unbolt pulsation damper from turbocharger and remove along with connecting hose.

Manual gearbox:

Detach supply hose -B- for clutch master cylinder, lift clear and tie in place, or clamp off supply hose -B- for clutch master cylinder with a commercially available tool, e.g. Hazet 4590, and then pull off.

Dual clutch gearbox:

Remove gear selector cable from ball head and cable support ⇒ 7-speed dual clutch gearbox 0AM; Rep. gr. 34; Selector mechanism.
Remove selector lever from selector shaft on gearbox ⇒ 7-speed dual clutch gearbox 0AM; Rep. gr. 34;.

Continuation for all models:

Mark and unscrew brake lines from brake master cylinder -1- and immediately seal brake lines with plugs from repair kit Part No. 1H0 698 311 A.
Pull vacuum hose out of brake booster.
Separate brake pedal from brake booster ⇒ 5.2.1 Separating brake pedal from brake booster.

Remove hexagon nuts -arrows-.
Carefully remove brake booster from vehicle.
If brake booster sticks in holes, loosen both remaining nuts on mounting bracket.
Unscrew brake master cylinder from brake booster.
Remove heat shield (if installed).
Carefully take brake master cylinder out of brake booster.

Observe following points when installing:

Specified torques:

Brake booster to pedal cluster and plenum chamber 25 Nm bulkhead

Brake master cylinder to brake booster

25 Nm

Brake lines to brake master cylinder

14 Nm