Master cylinder, removing and installing: Notes

WARNING: This page is about a different car, the 2008 Audi A4, 2007 Audi A4, 2006 Audi A4, and 2005 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.

Special tools, testers and auxiliary items required

Fig 1: Identifying Hose Clamps 3094

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Hose clamp 3094

Fig 2: Identifying Spark Plug Connector Pliers V.A.G 1922

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Spark plug connector pliers V.A.G1922

Removing

Observe the notes on removing and installing master cylinder and slave cylinder → Notes on removing and installing master cylinder and slave cylinder .

CAUTION:

Follow steps required when disconnecting battery →
- 27 BATTERY, STARTER, GENERATOR, CRUISE CONTROL
- 27 BATTERY, STARTER, GENERATOR, CRUISE CONTROL for Cabriolet
.

Fig 3: Identifying Plenum Chamber Cover & Removing Rubber Seal

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Pull off rubber seal on plenum chamber in direction of - arrow -.
Remove cover - 1 - from plenum chamber.
With ignition switched off, disconnect battery Ground (GND) strap →
- 27 BATTERY, STARTER, GENERATOR, CRUISE CONTROL
- 27 BATTERY, STARTER, GENERATOR, CRUISE CONTROL for Cabriolet
.

Fig 4: Removing Securing Clips And Cowl

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Use screwdriver to pry off the two caps - 3 -.
Remove nuts - 4 - and detach the two wiper arms - 2 -.
Pull off clips - 1 - and detach cowl panel grille - 5 -.

Fig 5: Removing Screws And Cover From E-Box In Plenum Chamber

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Take the electronics box out of the plenum chamber as follows:

Remove bolts - arrows - and take off cover.

Fig 6: Using Screwdriver To Remove Retainer Bar And Engine Control Module (ECM) J623

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Use screwdriver to carefully pry off retaining strap - arrow -.
Lay aside engine control module with connectors attached.

Fig 7: Connector At Connector Rail And Wire

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Disconnect connectors - 2 - at console.
Disconnect electrical wiring connection - 1 -.

Fig 8: Locating Auxiliary Relay Carrier Catches

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Release catches - arrows - and lift auxiliary relay carrier out of electronics box.
Pull engine wiring harness together with rubber grommet out through opening in electronics box.

Fig 9: Electronics Box Nuts

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Remove nuts - arrows - and lift out electronics box - 1 -.

NOTE:

In the following steps make sure that no brake fluid escapes into the plenum chamber or onto the transmission below. If this does happen, clean the affected area thoroughly.
When performing work in the footwell, put cloths on the carpet to protect it from possible brake fluid spills.

Fig 10: Identifying Brake Fluid Reservoir Return Hose Grommet

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Clamp supply hose - A - from brake fluid reservoir using hose clamp 3094. Disconnect hose from master cylinder and plug hose.
Remove rubber grommet from bulkhead above connection line for supply hose.
Pry out retaining clip - C - using a screwdriver and pull out line/hose assembly - B - slightly.

Fig 11: Location Of Brake Fluid Reservoir Dowel Bolt

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Remove brake fluid reservoir bolt - 1 - and disconnect connector for brake fluid level warning contact downward.

NOTE:

Brake fluid reservoir must not be removed.

Fig 12: Location Of Brake Servo Securing Bolts

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Remove vacuum line to brake servo - 1 -.
Remove two TORX bolts - arrows -.

NOTE:

To simplify the illustration, the brake fluid reservoir has not been included.
The brake fluid reservoir must be moved slightly to the side in order to unscrew the upper TORX bolt.

Remove storage compartment on drivers side →
- 68 - INTERIOR EQUIPMENT
- 68 - INTERIOR EQUIPMENT for Cabriolet
.
Removing over-center spring → Over-center spring, removing and installing .

Fig 13: Brake Pedal At Brake Servo

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Disconnect brake pedal from brake servo → 47 - BRAKES - HYDRAULIC COMPONENTS .

Fig 14: Locating Steering Column At Steering Gear And Disconnecting Connector On Clutch Pedal Switch, Brake Pedal Switch And On Accelerator Pedal Module

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Disconnect steering column from steering gear - arrow A - → 48 - STEERING .
Disconnect connectors from clutch pedal switch - 1 - , brake light switch - 2 - and accelerator pedal module - 3 -.
If installed, disconnect connector from clutch pedal starter interlock switch F194.
Remove securing bolt for mounting bracket - arrow B - and remove entire pedal cluster.

Fig 15: Pressing Retainer Together And Detaching Clutch Pedal From Master Cylinder Using VAG 1922

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Release master cylinder operating rod from clutch pedal as follows:

NOTE:

When releasing the operating rod, make sure that clutch pedal does not collide with mounting bracket for clutch pedal switch - arrow -. The mounting bracket could otherwise break off.

Apply spark plug connector pliers V.A.G1922 in clutch pedal recesses, press on sides of retaining clip and detach clutch pedal from master cylinder.

Fig 16: Identifying Retaining Clip, Clutch Pedal, Bolts And Master Cylinder

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Remove retaining clip - 1 - and remove clutch pedal - 2 -.
Remove bolts - 3 - and remove master cylinder - 4 -.