There are two types of slave cylinder. The most common kind is one that is basically a piston in a sleeve that is bolted to the side or top of the transmission where it bears against the clutch fork. Usually, this type is relatively easily accessed, easily replaced, and then easy to bleed.
The other kind of slave cylinder sits inside the transmission bell housing. In this type, there is no clutch fork or throw-out bearing, but the slave cylinder encircles the transmission input shaft where the throw-out bearing would otherwise be.
From there, it acts directly upon the fingers of the pressure plate. Because of this, it has the advantage of eliminating several moving parts. On the other hand, it has the disadvantage of being more complicated itself and of requiring the removal of the transmission to be in service.
Replacement Costs of Slave Cylinder
To be able to properly illustrate the varying costs of replacing a clutch slave cylinder in different vehicle models, a labour rate of £70 per hour will be used for the following:
- For a 2002 Honda Civic with a 1.7-liter engine, the labour time is estimated at 1.1 hours. A factory slave cylinder price is about £115, and a non-OE part costs about £30. The total cost to complete the job would be about £190 using OE parts or £105 using aftermarket parts.
- For a 2007 Jeep Wrangler with a 3.8-liter engine, the labour time is estimated at 0.9 of an hour. A factory slave cylinder costs about £65, and a non-OE part costs about £30. The total cost to complete the job would be about £130 using OE parts or about £95 using aftermarket parts.
- For a 2008 Volkswagen GTI with a 2.0-liter engine, the labour time is estimated at 7.9 hours (requires transmission removal). A factory slave cylinder costs about £90, and an aftermarket part costs about £73. The total cost to complete the job would be about £645 using OE parts and about £625 using aftermarket parts.
- For a 2005 Toyota Corolla with a 1.8-liter engine, the labour time is estimated at 1.2 hours. A factory slave cylinder costs about £82, and a non-OE part costs about £13. The total cost to complete the job would be about £165 using OE parts and about £100 using aftermarket parts.
In all the above cases, the time for bleeding the system should be included in the labour time. A small amount of brake fluid is needed to refill the hydraulic clutch system, but would be a relatively inconsequential cost.
Clutch Slave Cylinder Replacement
On a vehicle with a manual transmission, there are a couple of ways to work the clutch fork to release the clutch. One way is with a cable operated by the clutch pedal, and the other is with a hydraulic system.
In the hydraulic system, there is a clutch master cylinder that is operated by a pedal. This sends pressurised fluid down a line to a slave cylinder on the transmission.
A hydraulic clutch system uses brake fluid, which is the same as the brake system. The moving parts can wear and fail in the same way as brake components. The seals that hold pressure can leak; they can allow air to be drawn in, which prevents good operation; or they can seize up internally.
If a hydraulic system isn’t working right, such as lacking external leaks, it’s not always easy to figure out which of the two parts is the cause; whether it’s the master cylinder or the slave cylinder. Usually, this is done by blocking off the master cylinder and seeing if it builds and holds pressure. If it does, it’s probably okay, and the slave cylinder is likely the issue.
What Else Might be Recommended
The most closely related thing would be the clutch master cylinder. If one part of the system fails from wear, age, or contamination, the other part of the system may be in a similar condition even if it hasn’t failed yet.
It’s very common to replace the clutch master and slave cylinders together. The master cylinder is usually a little more difficult to replace than the slave cylinder, requiring work under the dash as well as in the engine compartment. However, the clutch master cylinder replacement cost is usually about the same as far as parts cost is concerned.
There is a large amount of labour involved in replacing a clutch slave cylinder that requires transmission removal. The clutch assembly itself should be closely inspected and replaced if it shows significant wear to avoid having to remove the transmission again for as long as possible.
Depending on driving habits and conditions, a clutch assembly should last about 100,000 miles. If mileage is close, it is prudent to take the opportunity to replace the clutch while it is easily accessible.