Removing and installing brake servo, LHD vehicles

Special tools and workshop equipment required

Brake filling and bleeding equipment -VAS 5234-

Torque wrench -V.A.G 1331-

Sealing tool -T10249-

Adhesive strip remover -VAS 6349-

Drill, cordless screwdriver or grinder

Removing

• If vehicle has a coded radio, note radio code or, if necessary, request it.
• Disconnect battery → Electrical system; Rep. gr.27
• Remove battery → Electrical system; Rep. gr.27.

Vehicles with diesel engine:

• Remove engine cover panel.
• Loosen hose clip -1- and remove air intake hose and air filter housing → Rep. gr.23.

On »R« vehicles:

• Loosen hose clips -2- and -3-.
• Remove air intake hose -1- and air filter housing → Rep. gr.24.

Continuation for all models:

• Remove battery tray → Electrical system; Rep. gr.27.
• 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-.

Vehicles with manual gearbox:

• Pull off supply hose -1- for clutch master cylinder, seal it using sealing tool -T10249- and tie it up, or clamp off supply hose -1- for clutch master cylinder using commercially available tool, e.g. Hazet 4590, and pull it off.

Continuation for all models:

• Disconnect connector from brake fluid level warning contact -F34--3-, from vacuum sender -G608--2- (if fitted) and from brake light switch -F--1-.
• Dissipate vacuum in brake servo by depressing brake pedal several times.
• Pull vacuum hose out of brake servo.
• Unscrew brake lines from brake master cylinder and seal brake lines with plugs from repair kit Part No. 1H0 698 311 A.

Vehicles with 7-speed dual clutch gearbox:

• Remove selector cable and cable support bracket from gearbox → Rep. gr.34.

Continuation for all models:

• Remove dash panel end cover on driver side → General body repairs, interior; Rep. gr.70.
• Remove footwell cover on driver side → General body repairs, interior; Rep. gr.68
• Remove centre console cover on driver side → General body repairs, interior; Rep. gr.68.
• Remove storage compartment on driver side → General body repairs, interior; Rep. gr.68
• Remove dash panel cover on driver side → General body repairs, interior; Rep. gr.68.

• Remove knee airbag -1- → General body repairs, interior; Rep. gr.69.

• Remove footwell vent on driver side → Heating, air conditioning system; Rep. gr.87.

• Remove control unit for data bus diagnostic interface -J533--3- and lay it to one side → Electrical system; Rep. gr.97.

• Unbolt -2- crash bar for brake pedal -1-, detach it, and lay it to one side → General body repairs, interior; Rep. gr.70.
• Separate brake pedal from brake servo → Chapter.

• Unscrew bolts -1- and fold footwell trim -2- in direction of arrow towards vehicle interior.

• Unscrew nuts -3 and 4- from brake servo.
• Pull brake servo off plenum chamber bulkhead, applying force to separate bonded joint.
• Carefully remove brake servo from the vehicle.
• Unscrew nuts for brake master cylinder.
• Remove heat shield, if fitted.
• Carefully remove brake master cylinder from brake servo.

Installing

Install in reverse order of removal, observing the following:

• Remove all adhesive residue from plenum chamber bulkhead and, as needed, from brake servo. Use adhesive strip remover -VAS 6349- with a drill, cordless screwdriver or grinder for this purpose.
• Operate adhesive strip remover -VAS 6349- at low speed, working against direction of rotation.
• Renew gasket.
• Connect brake pedal to brake servo → Chapter.
• After installing, bleed brake system → Chapter and clutch.

Specified torques

→ Chapter

Crash bar → General body repairs, interior; Rep. gr.70.

Footwell vents → Heating, air conditioning system; Rep. gr.87.

Knee airbag → General body repairs, interior; Rep. gr.69.

Covers on driver side → General body repairs, interior; Rep. gr.68