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Clutch Slave Cylinder Replacement
Typical Cost: Medium - High
Mobile Repair? Yes depending on the vehicle
Typical Lead Time: 24 - 48 hours depending on part availability
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!
Typical symptoms that require the clutch slave cylinder to be replaced.
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.
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
What does this repair cover?
Unless otherwise stated, the quote for your clutch slave cylinder to be replaced will cover;
- The cost of the clutch slave cylinder (if external), the complete clutch kit (if concentric), and hydraulic fluid
- Coming to you or collection and return delivery (if still drivable)
- Fitting of the parts
- Disposal of the old parts (unless you request to keep them)
- VAT (if applicable)
- 12 months parts and labour warranty
What to search for on the ClickMechanic site?
Clutch slave cylinder replacement
Associated repairs
Clutch master cylinder replacement
Bleed hydraulic clutch release system
Clutch replacement
How much does it cost to have a clutch slave cylinder replaced?
The cost of a clutch slave cylinder replacement depends on your car and what parts your car's manufacturer recommends.
Find out what you could save by visiting ClickMechanic
https://www.clickmechanic.com/bookings/car
FAQ’s
Can you just replace a concentric slave cylinder and not the whole clutch kit?
Basically no, it comes as a kit and the clutch itself needs to be removed anyway, so you wouldn’t re-fit an old clutch, The other likelihood is that any escaping hydraulic fluid will have soaked into the clutch friction material, which will make them soft for one, but also as hydraulic fluid is essentially an oil, they will not work as efficiently.
Can I supply my own parts?
No, we will not fit customer supplied parts unless they are a brand new item, purchased from a dealership with the receipt as proof of purchase. There is no flexibility over this due to insurance and warranty issues.
What happens if the mechanic finds that the clutch slave cylinder doesn’t require changing and the problem is due to another issue?
In this scenario, the mechanic will provide a no obligation quote for the correct repair. Should you accept this, the mechanic can alter the booking accordingly. If you decide not to go ahead with the alternative repair, the mechanic can change the booking to a call out and diagnostic booking and charge according to the time spent with the vehicle and call out.