Clutch Slave Cylinder replacement & repair made easy

What does a clutch slave cylinder do?

The clutch slave cylinder receives the hydraulic pressure created by the clutch master cylinder when you press down on the clutch pedal. It then releases the clutch from the flywheel allowing you to change gear.

How does a clutch slave cylinder work and what are the components?

If you consider the clutch hydraulic system as if it were a balloon pump with a balloon on the end, the slave cylinder is the balloon. When the handle is pushed down (the master cylinder part), the balloon inflates under the pressure. This is quite simply how the slave cylinder works - force created at the master end, creates a pressure at the slave end.

There are two types of clutch slave cylinder, the external standard type and an type that is integrated with the clutch itself, called a concentric slave cylinder or CSC.

The external type is a simple piston that gets forced out under pressure and that pushes against the clutch actuator (or release arm) and moves the clutch plates away from the flywheel.

The concentric type works in a similar way, but it is part of the clutch itself and when the pressure is created it inflates and expands, which moves the clutch plates away from the flywheel.

Note

If your vehicle has an internal concentric slave cylinder, then this will require a complete clutch replacement. The reason for this is because the clutch has to be removed in order to replace it and you wouldn’t refit an old clutch but also, it is likely the clutch hydraulic fluid, which is basically oil, will have soaked into the clutch friction material and they will not last or may even simply not work. It would be similar to pouring oil onto your brakes pads!

How do you know there is something wrong with the clutch slave cylinder?

Usually, clutch slave cylinders do not completely fail, in other words, the pedal doesn’t suddenly lose all resistance and drop to the floor. Generally, the problem will start with having to pump the pedal to change gear or you gradually have to use more of the pedal travel to change gear. This isn’t always 100% true as with any mechanical operation, so it can occur if there is complete failure of the unit.

If you are able to, you can check the level of brake fluid in the reservoir under the bonnet, which will start to drop if there is a leak in the slave cylinder. You may also notice drops of fluid under the car, but this isn’t always the case with an internal concentric slave cylinder.

When should you consider a clutch slave cylinder replacement?

As soon as any issue arises with the clutch mechanism, it is important to get it checked as soon as possible before a breakdown occurs.

How common is a clutch slave cylinder replacement?

Being typical of any mechanical component that is in constant use that has rubber seals, clutch slave cylinders fail on all cars quite regularly.

How can I extend the life of my clutch slave cylinder?

There is little you can do to extend the life of a clutch slave cylinder, although taking a considered approach to changing gear may help extend its life more than if you are constantly ramming the clutch pedal down as fast as possible.

What happens during an external clutch slave cylinder replacement?

Changing external clutch slave cylinders is a routine repair for all mechanics and can be done both kerbside as well as in the workshop, providing it is safe to do so.
Whilst there are variations between manufacturers, the basics are pretty similar.

The mechanic will;

Assess the operation of the clutch mechanism
Remove the faulty unit and replace with a new one
Bleed the hydraulic system
Re-test the operation of the clutch mechanism.

What happens during the replacement of an internal concentric slave cylinder CSC)?

This is a completely different type of repair to the external cylinder type. The mechanic will have to carry out a complete clutch replacement, which may require the vehicle to be taken into the workshop, depending on the size of the engine or the vehicle's location.

For more information on clutch replacement, please refer to https://www.clickmechanic.com/help/articles/283/clutch-replacement

How much does a clutch slave cylinder replacement cost?

The cost of replacing a clutch slave cylinder depends on your car and what parts your car's manufacturer recommends using for the replacement. Find out what you could save by having your clutch slave cylinder replaced by ClickMechanic, by selecting your car at the top of this page!

Please note that if the system doesn’t return a price and requests you to complete a form, the most likely reason is that your car has an internal concentric slave cylinder. In which case you need to select a clutch replacement repair.