Removing and installing brake master cylinder, RHD vehicles

Note

Special tools and workshop equipment required

Brake filling and bleeding equipment -VAS 5234-

Torque wrench -V.A.G 1331-

Sealing tool -T10249-

Fitting location of brake master cylinder in RHD vehicles:

Removing

• If vehicle has a coded radio, note radio code or, if necessary, request it.

Vehicle with diesel engine:

• Remove engine cover panel → Rep. gr.10.

• Release and pull off fuel supply lines -1- and -2-.
• Separate plug-in connectors → Rep. gr.20.
• Unclip fuel lines -1- and -2- from retainer -arrow- on coolant reservoir -3-.

• Remove securing bolts -2-.
• Unscrew nut -1-.

• Open retainer -arrow- and unclip fuel lines -1-.
• Then lay fuel filter to one side.

• Release electrical connector -1- and pull off.
• Release catches using a screwdriver -arrow-.
• Place coolant expansion tank onto engine.
• Remove upper toothed belt guard → Rep. gr.15.

Vehicles with manual gearbox:

• If present, remove heat shield.
• To do so, remove clamping washer -4- from plenum chamber bulkhead.
• Open snaps -1- to -3- on heat shield.

• Pull return hose -2- for clutch sender cylinder -3- off brake fluid reservoir -4-.
• Seal return hose -2- for clutch master cylinder -3- with sealing tool -T10249--1- or hose clips to 25 mm -3094-.
• Raise and tie return hose -2- in place.

Vehicles with air conditioning:

• Evacuate refrigerant circuit → Heating, air conditioning; Rep. gr.00.
• Unscrew nuts -2- on refrigerant line -1-.
• Remove refrigerant line -1-.

Continuation for all models:

• Place sufficient lint-free cloths in area of engine.
• Draw off as much brake fluid as possible from brake fluid reservoir using brake filling and bleeding equipment -VAS 5234-.

• Remove heat shield -1- if present.
• To do this, unscrew bolt -3-.
• Pull heat shield -1- upwards out of retainers -arrows- on brake fluid reservoir -2-.

• Release connector -1- and pull off brake light switch -F--2-.

• Release electrical connector -2- for brake fluid level warning contact -F34- and pull it off brake fluid reservoir -1-.

• Pull out spreader rivet -3- in -direction of arrow-.
• Pull brake fluid reservoir -1- upwards off brake master cylinder -2-

• When doing this, gently press refrigerant line -1- upwards.

• Unscrew brake lines -1- from brake master cylinder -3-.
• Seal brake lines with sealing plugs from repair kit Part No. 1H0 698 311 A.
• Remove nuts -arrows-.
• Remove heat shield -3-.
• Carefully remove brake master cylinder from brake servo.

Installing

Install in reverse order of removal, observing the following:

• When assembling brake master cylinder with brake servo, make sure push rod is properly positioned in brake master cylinder.
• When joining brake master cylinder to brake servo, make sure seal → Item is properly seated.
• Ensure that seals → Item are correctly seated in brake master cylinder.
• Moisten sealing plugs → Item with brake fluid before pressing brake fluid reservoir into brake master cylinder.
• Bleed brake system → Chapter.

Vehicles with manual gearbox:

• Bleed clutch mechanism → Rep. gr.30.

Vehicles with air conditioning:

• Charge refrigerant circuit → Heating, air conditioning; Rep. gr.00.

Specified torques

→ Chapter „Assembly overview - brake servo/brake master cylinder, RHD vehicles“

→ Chapter „Connecting brake lines to hydraulic unit, RHD vehicles“

Toothed belt guard → Rep. gr.15

Fuel filter → Rep. gr.20

Air conditioning → Heating, air conditioning; Rep. gr.87

Front bleed valves → Chapter „Assembly overview - front brake caliper“

Rear bleed valves → Chapter „Assembly overview - rear brake caliper“