We know that the clutch slave cylinder helps the hydraulic clutch system prolong a clutch’s life because it automatically adjusts to when the main clutch slowly wears.
The self-adjusting slave cylinder was patented in 1967 and is still used in cars today. Its function is so important that if it gets worn out, it has to be replaced. If such is the case, how much do you pay for the clutch master and slave cylinder replacement?
Moreover, what are the symptoms that will tell us that a clutch slave cylinder already needs replacement? What causes a clutch slave cylinder to break down? How do we prevent such occurrence?
Replacement Costs of Slave Cylinder
The clutch slave cylinder replacement cost ranges between $175 and $840 depending on the model and year of your car. The cost already covers labor, clutch slave cylinder parts, as well as taxes and fees.
Auto repair shops and service providers can provide the replacement parts for $60 to $200, although it can go as high as $260, depending on the car being serviced as well as the availability of the components. Labor, on the other hand, depends on the service provider which ranges between $70 and $578, although it can be as low as $60.
Going straight to your nearest shop or looking for the nearest repair service company online like Repair Pal, Autozone; or reserving an appointment in sites as YourMechanic, Firestone or Auto-Lab may seem the easiest way to go, but there are some things you need to consider when you wish to have your clutch slave cylinder replaced.
Clutch Slave Cylinder Basics
A clutch slave cylinder is half of the slave-master components of the hydraulic clutch system found in manual-transmission vehicles.
When the clutch pedal is pressed, the master cylinder it is connected to will release brake fluid through the tube connecting to the clutch slave cylinder. The hydraulic pressure pushes the slave cylinder to extend a rod that presses against the lever or fork that engages the actual clutch, aiding in the smooth transition of gears.
When the clutch pedal is released, the clutch gets disengaged, allowing the slave cylinder return spring to push the brake fluid back to the clutch master cylinder. The hydraulic pressure will drive the master cylinder to return the pedal to its original height.
The engagement-release process holds true for clutch slave cylinders that are located outside the transmission. External slave cylinders are usually mounted to it with 2 bolts and the fork or rod activates the clutch pressure plate.
There are, however, car models that have a clutch system where the slave cylinder is inside the differential itself, thus, the slave cylinder and clutch release are part of a single unit and held by 2-3 bolts. When the clutch pedal is pushed and the brake fluid pressure is on the slave cylinder, the slave cylinder slides into the input shaft of the manual transmission. This direct contact eliminates the use of a clutch fork.
To find the clutch slave cylinder, look on the left-hand side of the bell housing which is the location on many vehicles. On some cars, you will have to look for the slave on the inside of the bell housing. It is on the input shaft of the transmission.
Wear and Tear
Like all other car parts, the clutch slave cylinder gets gradually worn through use. Wear and tear speeds up if the brake fluid is not regularly replaced every 24,000 miles or every 2-3 years since the brake fluid attracts atmospheric moisture which can cause corrosion to the hydraulic system.
When the clutch master cylinder goes bad, the slave cylinder soon follows; while a faulty slave cylinder would mean a malfunctioning hydraulic clutch system. Regardless of which component got worn out first, it is still advisable to replace the clutch slave cylinder. A faulty hydraulic clutch system keeps you from shifting gears properly until driving will become impossible and the transmission is damaged.
If the clutch slave cylinder is left unchecked and the hydraulic clutch system continues to be used, other issues will soon follow. The seal will go bad and the car will start leaking brake fluid.
Leaking fluid is replaced by air that gets into the clutch system. This makes the clutch pedal go soft and driving can become dangerous.
It is possible to drive a vehicle without a properly working clutch slave driver, but only when the differential is improperly shifted – which can cause further wear and tear to your car. Additionally, forcing your car to drive without a properly working clutch slave cylinder means that your vehicle may need to be push-started every time it stops.
Prolonging repair, therefore, will only increase damage to your car as well as the dollars spent on every repair, including the cost of brake fluid.
Symptoms of Clutch Slave Cylinder Malfunction
For the most part, the clutch slave cylinder helps the clutch pedal remain firm. However, if the pedal appears loose and if it feels the same way as you put your foot onto it, then it is very likely that the slave cylinder needs work.
Two other telltales that indicate that this device need work are:
If you ever spot any of the following problems with your car, have a mechanic or an auto repair shop properly diagnose as it could be a sign that your clutch slave cylinder is due for a replacement:
- Abnormal clutch pedal feel – air getting into your hydraulic system tube makes your clutch pedal go soft. Pushing the pedal has a mushy or spongy feel to it – the pedal sometimes sinks all the way to the floor and does not return to its original position if you remove your feet because the clutch is not properly disengaged when you attempt to safely shift your differential.
- Brake fluid leakage – if you see any leaks around the clutch pedal, on the floor of your driver’s seat or even on the engine bay, then a faulty clutch slave cylinder could be one of its culprits. Depending on its severity, the brake fluid leak could also be the one behind that spongy clutch pedal feel.
- Low brake fluid levels – consequently, if you have leaky clutch cylinders, this will reduce the amount of brake fluid you have in your hydraulic clutch system. It also means the tube contains air.
- Contaminated brake fluid – is your brake fluid in the hydraulic system tube dark or murky? This could mean that your slave cylinder’s rubber seals are worn out.
- Difficulty or inability to change gears – one of the things you need to check when you have an unusual difficulty in shifting gears is your car clutch system. This inability to shift becomes more evident as the clutch slave cylinder problem gets worse.
- Attempted forward motion – does your vehicle attempt to thrust forward even if you stop your vehicle in gear? If it does, then, you might want to have your clutch slave cylinder checked. This is also why some cars with this problem have to be push-started during ignition.
Clutch Slave Cylinder Replacement Process
Once your car has been diagnosed with a problematic clutch slave cylinder, the following steps are followed during the clutch slave cylinder replacement:
- Step 1: Inspection
Inspection is done to confirm the severity of the damage as well as to check for any additional repair work. The car has to be jacked up first so that it is elevated enough to work on, but not too high so that the mechanic can still work under the car hood.
A leak pan is placed underneath the slave cylinder to cover for any sudden leaks. The car hood is opened, the clutch master cylinder reservoir uncovered, and the brake fluid is sucked out with a vampire pump to ensure that the fluid does not fall on your car as this chips the paint job away.
The brake fluid is then checked for murkiness and dirtiness that indicate the severity of contamination. The rest of the hydraulic clutch system is checked, including the tubing that connects the master and slave cylinders, as well as the clutch pedal operation.
Another reason for the inspection is to see whether the clutch slave cylinder is externally or internally attached to the transmission. If the slave cylinder is internally connected to the differential, then the transmission has to be taken off during the removal process.
- Step 2: Removal
If the clutch slave cylinder is internally connected to the differential, the entire transmission is uninstalled first. From the slave cylinder, the hydraulic line or tube should be detached, with one end covered with a plastic bag wrapped in a rubber band to keep any remaining brake fluid from leaking.
The clutch slave cylinder is then detached from the differential housing and the rest of the brake fluid in the slave cylinder reservoir is siphoned by the vampire pump.
The clutch hydraulic line insulating caps are taken off, the master cylinder removed from the firewall, and the slave cylinder detached from the entire system. These three components will then be removed from the car with utmost care so as not to bend the hydraulic line or tube as it will break.
- Step 3: Preparation, Priming, and Air Bleeding
Prior to the replacement of the clutch slave cylinder, it must be ensured that the replacement cylinder is either of the same model or matches the car’s requirements. Before the installation of new parts, it is also important to check the new components for damage and that the seal is at the back of the clutch master cylinder housing.
Ideally, replacement of the clutch slave cylinder goes hand in hand with the hydraulic line and clutch master cylinder. This is because once a master cylinder gets worn, the slave will soon follow. It is, therefore, more economical to replace these parts in one repair job rather than having your car repaired in two or three separate repair jobs if you include the hydraulic line.
The process of setting up the new components is just the opposite of how it was dismantled, except that the cylinders have to be primed first. This is done by first connecting the clutch master cylinder with the hydraulic line using the brass punch as an extension.
When the master and slave cylinders are attached, the reservoir in the clutch master cylinder is then pumped with brake fluid up to ¼ inch from the top. A dripping pan is placed under the new slave cylinder before the latter has its bleeder screw removed so that the newly pumped brake fluid flows through the new clutch hydraulic set-up. This way, the components are primed and the air is removed out of the cylinder.
Initial drips from the slave cylinder bleeder hole may not be consistent at first. Brake fluid is pumped until a steady stream comes out of the outlet before resealing the bleeder. The mechanic will need an assistant to press the brass pump on the master cylinder in order to keep bleeding the air while the bleeder screw gets gradually tightened.
The final few twists to tighten the screw should be done when no more brake fluid gets out. Once this is done, the reservoir is continuously filled with brake fluid until the remaining ¼ is also filled before the master cylinder reservoir is resealed.
- Step 5: Installation of New Clutch Cylinders
The clutch slave cylinder is then reattached to the transmission differential housing. The clutch master cylinder, on the other hand, is reintroduced to its original location.
The hydraulic tube is carefully reattached to the cylinder without crossing the thread so as not to leak any fluid out. Mechanics use a special rubber grease to seal the connection between the hydraulic tube and the cylinders so it does not get worn out right away.
When the tube has been attached, a second bleeding is done by asking the helper to press on the clutch pedal and hold it, which will force the fluid to enter the hydraulic line and fill it up. The slave cylinder bleeder screw will have to be loosened from time to time so that the air trapped in the system is dripped out.
The master cylinder reservoir is refilled with brake fluid from time to time; repeating the entire process until all air has been removed before screwing the bleeder cap tight.
- Step 6: Final Set-Up
The complete system is finally reinstalled properly with the differential housing carefully returned through the engine compartment while ensuring that the hydraulic line is neither bent nor broken. The new hydraulic system is then bolted and secured properly, following the reverse order of the old component’s removal from the car.
Some of the accessories used to mount the hydraulic system like the cotter pin will have to be replaced with new parts. This is to ensure that the system does not get dislodged through future wear and tear. Universal cotter pin sets cost about $3.
- Step 7: Test Drive
Once everything is remounted, the car back on ground level, and the jacks removed, the car is then taken out for a test drive. Initial testing usually involves the car at standstill, with the engines running and the clutch pressed and released in between shifting gears to see how the pedal works.
The next part of the test is a drive around the block when the mechanic or driver applies a double clutch by pressing the clutch pedal down twice – the first one when sending the car gear to neutral and the second when going from neutral to another gear. This is to ensure the prevention of clutch and transmission gear damage.
Grinding and difficulty in gear shift when a double clutch is done could mean a clutch pedal assembly problem or a transmission failure. A smooth shift of gears and no grinding heard, on the other hand, means that the car is good to go.
A replacement of your car’s clutch slave cylinder usually takes 3 ½ to 4 hours, depending on the car model, manufacturer, and availability of the car parts. To ensure that your car repair time is not wasted:
- Call ahead and ask how long your car will take to get its clutch system repaired. You may need to give them the model and year of your car to get a more specific Estimated Time of Repair (ETR).
- Get a trusted mechanic or shop. If you do not have one, get a second or third opinion. See if the shop or mechanic has connections to car part dealers and check out the prices or if the shop or mechanic works with the parts you provide them.
Compare this with online prices and other dealers you know of and choose the most reliable car replacement parts source before settling with your chosen mechanic or shop.
- You may also replace your own clutch system at your own pace, provided that:
- It has been properly diagnosed (you can talk with a friend mechanic or shop owner),
- You have the right tools, and
- You have enough know-how on your car parts and how the hydraulic clutch system works.
Things to Consider
Opting for D-I-Y repair and replacement will save you not only time but also financial resources. This is because a clutch slave cylinder cost ranges between $10 and $260 if you buy it directly from the dealer or aftermarket shops. A clutch master cylinder, on the other hand, may cost between $12 and $700, although it can reach as high as $4,018.
A clutch hydraulic line costs from $34 to $350 and brake fluid ranges between $4 and $86
All the components have prices that depend on the car model and make the clutch cylinder is compatible with, as well as the brand of the cylinder and the availability in the market.
Considering the prices above, doing D-I-Y could cost you as little as $10-$13 if you only opt to change the clutch slave cylinder, with the additional $3 from a required new cotter pin.
For example, Nissan Altima has one of the lowest priced spare parts for clutch slave cylinder replacement at the price of $61. If you do the repair by yourself and by the spare part, you can actually spend for as low as $20 minus the cotter pin. If you have the same budget which is $61, you still have enough to spare to get yourself half a dozen of $4 brake fluid and still have some savings.
The downside to doing D-I-Y, however, is that you never can tell if the only culprit behind your clutch problem is the clutch slave cylinder.
Still, nothing beats having your car undergo regular inspection in the auto repair garage or an over-all inspection and repair as this reduces all the time, resources, and hassle you have to go through every time your car breaks down. It also prevents back jobs in case your car’s clutch problem is actually not rooted in the slave cylinder.
Always ask for a specific warranty to the mechanic or shop you are dealing with. This will tell you how a mechanic and/or shop will ensure precision in their work since back jobs are an expense and a liability on their part.
You can also buy the spare parts rather than rely on auto shops and repair service providers to do the buying. This way the only thing you need to splurge on would be the labor cost without really feeling guilty about it if you know your mechanic or repair shop is reliable.
As mentioned earlier in this article, clutch fluid should be changed regularly. Doing so not only prolongs your car’s clutch life, but brake fluid change is also the perfect time to inspect the clutch master and slave cylinder integrity.
A car’s hydraulic system is ideally good for 100,000 miles or 4-6 years, but cars used in city driving will need to undergo maintenance and fluid replacement more frequently than the required mileage.
Mechanics sometimes include brake fluid amount and integrity check during an oil change. If you are starting to feel any squishiness on your clutch pedal you may want to ask the mechanic to inspect the clutch hydraulic components for any possible wear and tear.
Use better replacements rather than inferior substitutes to ensure integrity and lifespan of the new components. Inferior parts will only increase costs because of back jobs and repeated repairs.