The clutch slave cylinder is located on the input shaft of the transmission. Whenever you depress the clutch pedal with your foot, you force fluid through the line that actuates the slave cylinder and pushes the release bearing, commonly referred to as the throwout bearing, against the diaphragm springs on the pressure plate. This disengages the clutch and allows you to change gears.
The clutch slave cylinder is a wear item, which means it's not going to last forever. Some of the reasons for the failure of the clutch slave cylinder are due to heat. As time goes on, heat cycle after heat cycle, it basically breaks the internal components down to the clutch slave cylinder. Ultimately, the clutch pedal will fall to the floor.
Some people have to replace the clutch slave cylinder before they have to service the pressure plate, clutch, and flywheel, while others may have the clutch slave cylinder last until they have to service these components.
Whenever you service all these components, you introduce air into the system, which means you have to bleed the entire system, including bench bleeding the new clutch slave cylinder.
In order to access the slave cylinder, you will need to remove the transmission. We have a seperate article detailing how to remove the transmission from your 2011-2014 Mustang GT.
Step 1: Gather Your Tools and Prepare
- Ensure you have all the necessary tools for the job.
- Verify the correct brake fluid for your vehicle (DOT 3 or DOT 4).
Step 2: Prepare the Vehicle
- Ensure the vehicle is safely raised, and the transmission is removed if necessary.
Step 3: Remove the Old Slave Cylinder
- Use a 12mm line wrench to loosen the tube nut from the slave cylinder.
- Loosen and remove the two 8mm bolts securing the slave cylinder to the transmission.
- Remove the slave cylinder and set it aside.
- Use a flathead screwdriver to depress the tabs on the clip securing the hard line to the transmission.
- Carefully remove the hard line from the transmission.
- Remove the clip from the hard line and reposition it back into the transmission.
Step 4: Prepare the Slave Cylinder
- For those reusing the existing slave cylinder, remove old fluid by depressing the cylinder to push out the fluid. Repeat this process.
Step 5: Bench Bleed the New Slave Cylinder
- Place the new slave cylinder on a workbench and remove any tags or labels.
- Fill a small cup with the correct brake fluid and submerge the end of the hard line into the fluid.
- Slowly actuate the cylinder to bleed it. Add more fluid to the cup to prevent air from entering.
- Position the slave cylinder back in place on the transmission and secure it with the retaining bolts.
Step 6: Refill and Bleed the Entire System
- Fill the clutch reservoir (or master cylinder) with the correct brake fluid for your application. Be careful not to spill on painted surfaces.
- Leave the cap unscrewed on the reservoir and begin bleeding the system. Slowly operate the clutch pedal with your hand.
- Check the reservoir regularly and add fluid as needed. Continue bleeding until the clutch pedal effort is consistent.
- Top off the reservoir to the max line and then fully install the cap.
Step 7: Reassemble the Vehicle
- Reinstall all components and ensure everything is secured properly.
