Clutch Hydraulic System: Service and Repair

Bleeding Clutch Hydraulic System
Remove transmission underbody protection if necessary.
Remove microfilter housing if necessary.





Unfasten nuts and remove clutch slave cylinder (pressure line remains connected).





Fit special tool 21 5 030 to the clutch slave cylinder (1). Press piston rod (2) completely into clutch slave cylinder with the help of the spindle.
Connect breather devise to brake fluid expansion tank.

Note:
^ Check relevant operating instructions for each device.
^ Charging pressure must not exceed 2 bar.





Attach breather hose to breather valve (1).
Hold clutch slave cylinder in illustrated position (refer to figure) with special tool 21 5 030.
Open breather valve (1).
Once brake fluid emerges without bubbles, withdraw piston rod (2) on clutch slave cylinder with the help of the spindle, then press back in.
If no air bubbles escape, close breather valve (1), otherwise repeat this process.

Caution: Never remove special tool 21 5 030 from clutch slave cylinder if the brake system is pressurized, otherwise the piston and push rod can be forced rapidly out of the clutch slave cylinder.

Switch off breather devise and/or remove from brake fluid expansion tank.





Slowly retract piston rod (2) of clutch slave cylinder (1) with special tool 21 5 030.
Remove special tool 21 5 030 from clutch slave cylinder (1).





Fit clutch slave cylinder to the transmission.

Installation:
Replace self-locking nuts.
Tightening torque:
Clutch master cylinder to bearing support 22Nm
Fitting screw, clutch master cylinder 22Nm
Clutch master cylinder to pedal assembly 9Nm
Clutch slave cylinder to clutch housing/transmission case 22Nm
Coupling bolts for hydraulic pipes 14Nm
Pressure accumulator for hydraulic unit 40Nm
Clutch position sensor to clutch slave cylinder(6 speed SMG) 2.5Nm
Correct brake fluid level in expansion tank.