Q&A for How to Bleed a Slave Cylinder

You have to pull the clutch pedal up by hand on some vehicles when bleeding.

Use a tube and a glass. Fill the glass with the fluid and connect one end of the tube to the bleeder. Place the other end in the glass full of fluid. Now as you press on the clutch pedal, it will blow the air out, and when you let go of the pedal, it will only suck up more fluid instead of air.

Check to make sure your bleeder valve is closed and the brake lines leading from the clutch master cylinder to the slave cylinder are in fact tight. If so, then most likely you still have air moving in the system. Bleed the system again, and check connections for leaks.

If the pedal is still soft, there is likely still air in the system. Continue to bleed it, or take it to a repair shop to have any leaks diagnosed.

On a right-hand-drive vehicle, it's on the right-hand side; the nipple is at the top of the gear box, and it's pointing upward.

Because there is still air in there. Keep bleeding it until you feel the resistance is not getting any stronger. Then, you have reached the maximum. If you bleed and bleed and get no resistance, you have a leak somewhere.

Your car should have a clutch pressure sensor in it, which only engages when enough pressure from the master cylinder signals that it can start. You might have to refill your car with fluid, because it may be low, and that's why it will not engage as easily.

It is probably an internal slave cylinder, which means it's inside the bell housing.

Most cars where this is the case have a plastic divider in the brake fluid reservoir, so even if the 'clutch half' of the reservoir has air in it or has completely emptied during bleeding, the 'brake half' of the reservoir still contains fluid and doesn't allow air to enter the brake system. This is also a safety measure: in the event of a leaking clutch system, at least your brakes keep working.

Go through all the joints. There could be some leaks, or you were not able to bleed it properly. Try bleeding it again til all the air in the tube is gone, and always monitor the fluid level in your reservoir.

You still have air in the system. You can remove the master cylinder and assembly to burp the system, then reinstall and gravity bleed the slave cylinder. There are videos on YouTube you can watch if you're not sure how to do it.

The flare on the end of the tube may have been damaged or corroded. Inspect the end of the tube to ensure that there is a nice even flare all of the way around. If you see any of the above symptoms, either cut and reflare the end, if the tube is long enough to do so, or replace the tube. Additionally, make sure that there is no debris or obstruction where the tube connects and that the threads are not damaged.

Remove nipple and replace with bleed screw. To ensure correct thread, take nipple with you to brake & clutch shop for thread comparison.

It’s not a must but it’s an option for catching the brake fluid so it doesn’t get all over your engine and onto the floor.