Clutch Slave Cylinder Replacement and Bleeding

Introduction

The clutch slave cylinder is mounted inside the clutch housing and actuates the release lever directly. Replacement requires removing the starter to gain access; the full starter removal procedure is in ELECT-02 (Starter Removal and Installation).

The clutch hydraulic system shares brake fluid with the brake master cylinder reservoir. DOT 4 brake fluid is specified.

Note: Keep the brake fluid reservoir at or above the minimum level throughout the bleeding process. Running it dry introduces air into both the clutch and brake hydraulic circuits.

Note: The clutch master cylinder supply line taps from a high point on the reservoir. If the reservoir runs low enough to uncover that port, air will enter the clutch circuit even if brake fluid is still present.

Other Procedures Referenced

• ELECT-02 Starter Removal and Installation

Tools

• Metric socket and wrench set
• Jack stands
• Floor jack
• DOT 4 brake fluid
• Clear plastic tubing (for bleeding)
• Container to catch fluid
• Mityvac vacuum pump (Method 3 only)

Slave Cylinder Replacement

1. Raise the rear of the car higher than the front and support on jack stands. This orientation helps bleed air from the system.

2. Remove the starter per ELECT-02 to expose the slave cylinder mounting location on the clutch housing.

3. Place a drain pan beneath the slave cylinder before disconnecting the hydraulic line.

4. Disconnect the hydraulic supply line from the slave cylinder. Plug or cap the line immediately to minimize fluid loss.

5. Remove the slave cylinder mounting bolts and withdraw the cylinder from the clutch housing.

6. Install the new slave cylinder in the housing. Torque the mounting bolts to 21 Nm / 15 ft-lb.

7. Reconnect the hydraulic supply line.

8. Bleed the system using one of the three methods below before reinstalling the starter.

9. Reinstall the starter per ELECT-02 once bleeding is complete and verified.

Bleeding — Method 1 (One-Person, Pre-Installation)

This method works best when the slave cylinder has been removed or is not yet installed. The shaft of the slave cylinder itself acts as a pump.

1. With the rear of the car raised higher than the front, fill the brake fluid reservoir to the maximum mark.

2. Attach a length of clear plastic tubing to the bleed nipple on the slave cylinder. Place the free end in a container below the nipple.

3. Open the bleed nipple approximately one turn.

4. Manually push the slave cylinder shaft in and out repeatedly, drawing fluid through the system and expelling air bubbles through the tubing.

5. Continue until no air bubbles appear in the tubing. Close the bleed nipple.

6. Check and top up the reservoir.

Bleeding — Method 2 (Two-Person, Pedal Pump)

Traditional pressure bleeding using the clutch pedal. Requires an assistant inside the vehicle.

1. With the rear of the car raised higher than the front, fill the brake fluid reservoir to the maximum mark.

2. Attach clear plastic tubing to the bleed nipple. Place the free end in a container partially filled with brake fluid (keeping the tube submerged prevents air re-entry).

3. Open the bleed nipple approximately one turn.

4. Have the assistant press the clutch pedal to the floor and hold it.

5. Close the bleed nipple. Have the assistant release the pedal slowly.

6. Repeat steps 4–5, checking the reservoir level between cycles. Top up as needed — never allow the reservoir to run dry.

Note: During the first few pedal strokes the clutch pedal may go to the floor and stay there. It must be lifted manually before the next stroke. This is normal when significant air is present in the system.

7. Continue until fluid expelled from the tubing is clear, free of bubbles, and the pedal has a firm feel throughout its travel. Close the bleed nipple.

8. Top up the reservoir to the maximum mark.

Bleeding — Method 3 (Mityvac Vacuum Pump)

Suitable for one-person use. A vacuum pump draws fluid through the circuit without pedal actuation.

1. With the rear of the car raised higher than the front, fill the brake fluid reservoir to the maximum mark.

2. Attach the Mityvac adapter to the bleed nipple on the slave cylinder.

3. Open the bleed nipple approximately one turn.

4. Apply vacuum with the pump and draw fluid through the system. Watch the clear tubing for bubbles.

5. Monitor the reservoir frequently and top up before it can drop below the minimum mark.

6. Continue until no bubbles appear in the drawn fluid. Close the bleed nipple.

7. Release vacuum and disconnect the Mityvac. Top up the reservoir.

Verification

After bleeding by any method, depress the clutch pedal fully and hold it for 30 seconds. The pedal should remain firm with no tendency to slowly sink toward the floor. A sinking pedal indicates residual air or a leak at the slave cylinder, master cylinder, or line connections.