Logic of naming actuators in VW-group is simple it contains "N" + actuator number. The actuator number is unique. Here you can find fitting location, connectors and some basic information about actuators.

To our mind, actuators information is reference, so there is only simple search by number.


Audi R8 42 (2007- )

Mode of operation of clutch adjuster valve -N255

The clutch actuator valve -N255 acts as a proportional valve regulating the volumetric flow to the clutch slave cylinder with release bearing. The piston in the clutch slave cylinder attempts to keep the cylinder chamber empty based on a spring force.

Characteristics of the left side curve:

B = Volumetric flow/oil flow in l/min

A = Current consumption in A


The valve N255 operates with two chambers and three hydraulic ports:

-1- = Oil sump/tank

-2- = Clutch slave cylinder

-3- = Pressure accumulator

When no power is connected to the valve, the hydraulic fluid flows out of the clutch slave cylinder back into the tank and the clutch is fully open (hydraulic ports 1 and 2 connected).

As soon as the valve current reaches the rising slope of the curve, a proportional oil flows into the clutch slave cylinder.

The piston in the clutch slave cylinder begins to close the clutch (hydraulic ports 2 and 3 connected). When the current is reduced to the low-level plateau (hydraulic port 2 not connected) the piston remains at the position it has reached in the clutch slave cylinder. A further reduction in current causes a proportional oil flow to flow out of the clutch slave cylinder again when the falling slope is reached, and the clutch begins to open.



Risk of injury from highly pressurised

hydraulic oil.

A Depressurise hydraulic system; see Workshop Manual.


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