Clutch transmitter and receiver for Mercedes W201

Clutch master and slave cylinders for classic cars

The hydraulic clutch control system comprises two cylinders and a closed circuit.The master cylinder, which is linked to the pedal, pressurises the fluid; the slave cylinder, located at the gearbox, converts this pressure into force on the clutch fork or the clutch release bearing. Our range covers both components in original or manufacturer-equivalent specifications, to maintain the factory pedal travel and slip point.

Identifying which component has failed

• Leak at the master cylinder: damp patches behind the pedal, on the dashboard or on the driver’s side carpet. The fluid level in the reservoir drops without any visible leak at the wheels.
• Leak at the receiver: seepage around the clutch housing, sometimes a streak down the side of the gearbox. On an internal, concentric receiver, nothing is visible and the fluid leaks into the bell housing.
• Air in the system: the pedal regains firmness after several rapid presses. This is not a sign of wear; it is a sign of air ingress, and therefore of a leak somewhere.

If in doubt, replacing both parts avoids having to remove them a second time: the dismantling process is the same and the system will need to be bled again anyway.

How to choose the correct part number

On the same vehicle, two part numbers may coexist depending on the model year or gearbox. Three factors distinguish them:

• The piston diameter, which determines the stroke ratio between the pedal and the fork. A different diameter results in a clutch that engages too early or does not disengage completely.
• The type of connection – threaded or quick-release – and its orientation. This is what changes most frequently during production.
• The position of the receiver: external on the bell housing or concentric around the shaft. A concentric receiver requires the gearbox to be removed: it is best to change it whilst replacing the clutch.

The compatibility guidelines listed on each product sheet allow you to check these points before ordering.

Bleeding and fluid: the step that determines the outcome

A new hydraulic system that has not been properly bled will exhibit exactly the same symptoms as a worn one. Use the fluid recommended by the manufacturer, usually from the DOT 4 family, and never mix two different families: the additives are not compatible and will damage the seals. On set-ups where the receiver is higher than the master cylinder, conventional bleeding using the pedal leaves an air bubble at the highest point: bleeding by gravity – with the reservoir cap open and the screw loosened – solves the problem that twenty pedal strokes will not resolve.

Price of a clutch master cylinder or slave cylinder

This is the question that arises immediately after the diagnosis. The price difference between two part numbers comes down to three factors: the position of the receiver (a concentric model being more expensive than an external receiver), whether or not the part number includes the connector and hose, and whether the part is available as an original equipment part rather than an equivalent. On an older vehicle, the cost of the part is rarely the main issue: it is the labour involved in removing it that is expensive, which is why it makes sense to replace both the sender and receiver during the same service.