Removing the Clutch Master Cylinder

PROCEDURE

Remove as much fluid as possible from the brake fluid reservoir (e.g. with an old syringe).

Unscrew the left-hand shelf under the instrument panel (see Interior).
Place an old rag under the master cylinder, disconnect the supply hose and let the remaining fluid drain into the rag.

In the engine compartment, to the left of the brake booster, unscrew the pressure line to the slave cylinder.

Unscrew the two internal hex bolts securing the master cylinder.

Pry off the retaining clip of the pivot pin (pedal to master cylinder connection) and push out the pin.

The master cylinder can now be removed.

When installing a new master cylinder, adjust the pushrod acting on the master cylinder piston so that the clutch pedal sits approximately 10 mm above the brake pedal.

Important: the return spring must return the pedal correctly. In its rest position the pedal must not contact the pedal bracket.

To adjust, loosen the locknut on the pushrod and turn the rod left or right about its own axis. Then retighten the locknut.

Remove air from the clutch hydraulic system (bleed).

Note: the clutch pedal on the Audi 80 is fitted with a spring located above the dead center. It assists pressing the pedal, but after the pedal is released it returns the pedal to its rest position. If the pedal does not return, air has entered the hydraulic system, or the pedal bearings or spring are seized.