The slave cylinder is part of the hydraulic clutch system in vehicles with manual transmission. When the master cylinder or the receiver cylinder starts to leak fluid it must be replaced with new brake fluid. Adding it also means introducing air into the system which creates a slight or non-existent friction when you press the pedal. To purge the air from the system you must remove it from the receiver cylinder. The following article describes 3 ways to do this.
Steps
Method 1 of 3: Purge a Receiver Cylinder Manually
Step 1. Lift the part of the vehicle where the engine is off the ground, securing it with supports; then find the purge valve
Step 2. Ask a helper to sit inside the vehicle and press and hold the clutch pedal all the way down without letting go, until you tell them
Step 3. Go under the vehicle and find the receiver cylinder
If it is not visible in some vehicles it may be inside the transmission (as part of the release bearing) and outside the transmission in most vehicles. Check the repair manual for your vehicle make and model to help you find the receiver cylinder.
Step 4. Loosen the purge valve with a wrench and hold a pot or similar and a rag to catch the liquid that comes out
Leave it open to see if any liquid comes out due to gravity, this could also let the air out.
Step 5. Close the valve as soon as it seems that all the air has gone out
Step 6. Release the clutch pedal (only after the valve has been closed)
It will probably stay on the ground and will have to be pulled up.
Step 7. Repeat by pressing the pedal, opening the bleed valve to let the air out, closing the valve and lifting the pedal until the clutch creates pressure and the pedal seems normal again
Step 8. Check that the brake fluid level in the reservoir is correct and add some if necessary
Method 2 of 3: Purge a Receiver Cylinder with a Vacuum Pump
Step 1. Get a manual vacuum pump for purging at the auto parts store
Step 2. Lift the vehicle to access the purge valve
Step 3. Ask a helper to depress the clutch pedal
Step 4. Loosen the purge valve and engage the vacuum pump
Step 5. Pump the brake fluid into a clear container until there are no more air bubbles coming out of the hose
Step 6. Close the purge valve
Step 7. Lift the clutch pedal off the ground by pulling brake fluid into the master cylinder and testing pedal free play
If it is still soft, bleed more air.
Step 8. Check the fluid level in the reservoir:
add if necessary.
Method 3 of 3: Purge a Receiver Cylinder with a Hose
Step 1. Get a small plastic tube at the auto parts store or fishing supply store
Step 2. Lift the vehicle
Step 3. Push one end of the hose onto the bleed valve and insert the other end into a transparent bottle half full of new brake fluid
Step 4. Bleeding procedure:
have a helper depress the clutch pedal while you loosen the bleed screw on the slave cylinder. The air will enter the container making bubbles in the brake fluid, where the air cannot return to the receiver cylinder.
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Tighten the bleed glass and ask your assistant to release the clutch pedal.
Bleed a Slave Cylinder Step 21 -
Repeat the process until you no longer see bubbles in the brake fluid.
Bleed a Slave Cylinder Step 22
